Some care only about their success (Rawls/The Reporter who makes up stuff)
Some care about the greater good but sacrifice it for personal success (Mayor Littlefinger)
Some want the organization to succeed (Sgt Fatso)
Some want to do good but are thwarted (Daniels & the editor who's name I can't remmeber)
Some do bad and throw it all away trying to do good (McNulty)
And there's many more. Ultimately that's what the show is about.
I think, however, that that choice of these characters, motivations and stories fits within the larger theme I described above.
But the show was definitely not in any way about the reality of the drug trade because it didn't depict the reality of the drug trade, especially the drug trade in Baltimore (if anything, it has vague similarities to the 80s-early 90s drug trade in Chicago.) Yes, I know he worked at the Baltimore Sun. The Corner was exactly authentic Baltimore. Even Simon would tell you that The Wire isn't.
The drug trade was a setting for making statements and playing out thought experiments about morality, power, and institutions (which you've pointed out from your perspective.) But if you see it as an accurate reflection of the drug trade anywhere, you're being deceived by fantasy fiction.
As for the non-drug side, well, let me say this. I went to college with a number of people from the DC political circuit, and they would get together each week to watch The Wire and drink and laugh. The reason for their laughter? They personally knew the people in the show that the characters were quietly depicting, and would find their portrayals accurate or hilarious. There were more than a few articles that came out when the series first aired of local noteworthies accusing The Wire of slander, to which The Wire's writing team would respond: "What made you think you were this character?"
But yes, ultimately I agree with you. The Wire is a fiction intended to be very close to reality, to make a point about the state of that reality. I think one of the major points, is the one I wrote above.
Game b recognizes that much of the world is subject to coordination problems (more evocatively called 'Moloch traps' or 'Prisoner's dilemmas')[1]. Game b thinking also recognizes both that the best outcome for a competitor within the current system is less optimal than the default outcome for a participant in a better system, and that any attempt to reform the current system requires viability within it.
Game a is therefore the game of being successful in the current imperfect system. Game b is the game of reforming it to make good outcomes easier for everyone to achieve. In some sense, Game b includes Game a, since staying viable in Game a is required to participate in Game b. But prioritizing Game b often leads to a different strategy for Game a than seeking maximum success in Game a.
Like I said, that's my take and likely my take on a Tuesday morning alone - but I'd be happy to discuss it further with you if you're interested.
[1]https://slatestarcodex.com/2014/07/30/meditations-on-moloch/
The main message of the show, as I viewed it, was:
The drug trade is fundamentally an outgrowth of a society that thinks in individualist terms, but lacks either the social collective and moral knowledge or the social collective and moral willingness to think outside of those individualist terms and individualist responsibilities sufficiently far enough to fix the issue.
This is because everyone in the show is acting as a rational agent following their own personal incentives. And in aggregate, these personal incentives become social forces that guide the actions of the institutions these people create in order to further their pursuit of these personal incentives. These are collectively referred to as "the rules of the game".
The show goes to extreme length to show, over and over again, that so long as everyone is following their individual incentives, IE following the rules of the game, it is NOT possible to solve the drug trade. The drug trade is itself a natural outgrowth of following personal incentives. (Why hamsterdam fails, why jimmy can't solve all crimes, why cedric can't reform the station himself, etc)
The show then makes very, very overt points to show that we all still have individualist responsibility, and our individual choices can and will make positive and negative impacts on the wider community and the people within our sphere of influence.
It then goes further and shows that by making the correct moral choices, by looking outside of our own individualist incentives, you CAN change the rules of the game for the people within your sphere of influence (Carter teaching humane police work, or opening a gym in a bad neighborhood). Similarly, doing the opposite and doubling down on personal incentive more ruthlessly will likely make the drug trade worse, but may personally benefit you more in the short term (Marlo, the journalist).
Phrased another way: if the drug trade could be solved by individual action, it would have been so already. The issues that plague Baltimore are issues that result from individualist thinking, and not being able to see outside of that.
The only person who really sits in a position of power large enough to successfully change the rules of the game, while acting solely as an individual, is the Mayor. But he is also very strongly incentivized NOT to do this, as doing so will require him to self-sacrifice his personal career as a politician. (He refuses to raise money from the suburbs, which are a voting block he would need to run for state Governor. He assumes that the suburban voters would punish him for that, even if he spent the money on Baltimore schools, due to their focus on their self-interest). So again, because he chooses to think in terms of personal incentives, the issue will not change.
The show, therefore questions why America and Americans act this way. The show is hoping that the reason we act this way is because we lack the knowledge about how everyone only thinking for themselves results in "the rules of the game" and puts everyone in this situation. It HOPES that if a show like The Wire exists, and teaches everyone this fact, then the individual characters in the show might look up for a moment, and demand, collectively, that the rules of the game change, by thinking outside of their own personal station in life. You will notice meaningfully absent from any character in the show is any type of character that actively attempts to do this, perhaps by organizing a social movement for meaningful social change, collectively, at the community level. This is what the writers talk about when asked "what should people do."
The show fears that people don't know, because they don't care. That people are fine with the pain and suffering that comes from the drug trade, so long as they get to pursue their individual incentives. To counter this, the show tries to point out that the characters that go the first path, and make the conscious choice to benefit their local community by thinking outside their own situation (the boxer guy, carter, bunny) all wind up happier and with better lives, than the ones who "succeed" at the game on individualist terms (marlo, barksdales, sobotka), in the long term.