But what gives the politicians the incentives to care about We the people? I'm just trying to challenge the notion that government inherently cares about The People because it's chartered to do so, whereas companies supposedly are chartered to care about only themselves.

Accountability to the electorate isn't just theoretical. Politicians are faced with elections every 2, 4 or 6 years. No, this isn't a perfectly efficient model of accountability, but there's been this meme going around recently that electoral accountability simply doesn't exist, which is just ridiculous. You don't even have to go hunting for examples: the dramatic shift in who held the power in the recent debt ceiling/shutdown hostage negotiations was 100% because of the way polls were shaping up. Contrast that with the 2011 shutdown when 1) Obama was facing an election and thus had to tread more carefully and 2) public opinion was split roughly equally against both sides. In that case Republicans were able to extract relatively significant concessions based entirely on the fact that Obama didn't want to blow up the world economy (depending on your level of cynicism, perhaps because he knew that he'd get flak for it in the upcoming election).

tl;dr: Gov't isn't assumed to care about the people's needs "because it's chartered to do so", but rather because they have specific and explicit dependencies on public approval. By contrast, companies have an explicit dependency on their customers (and shareholders). Everyone else and the externalities that they face are completely irrelevant as far as incentive structures for a company.

Well for what it's worth, I don't think it's a new meme, it's probably as old as libertarianism itself.

I'm glad your argument isn't about how the government is supposed to represent The People "at least in theory", I find that one rather funny given how people of my stripe are usually accused of only thinking in theory.

As much as I want to, I can't convince myself of the aforementioned meme wholesale, there must be some counterbalance or we'd all be slaves. But I want people to break out of what at least seems to me to be the notion that while private companies are selfishly motivated, they can invent the institution called government that's free of perverse incentives and selfishness just because they think society needs it to function.

Your point about nationwide approval of the government versus specific approval of companies is a good one. Consider some counterpoints: 1) the politicians need not pander to everyone, only those who care to vote. 2) expanding on the reluctance to bother voting, there's reluctance to be informed, since your vote had miniscule chance of effecting your life. It's known as rational ignorance, Bryan Caplan has a lot to say about it if you're interested in looking it up. In contrast, choosing one company over another always has immediate effect.

Another way to think about it is to ask "Where does the incentive come from to keep members of your family alive, healthy, and happy?"

A government defines a group of people who tend to have some sort of patriotic emotional bond with each other, much like the emotional bond that ties a family together. This is why people all across America felt the pain of the 9/11 attacks despite the fact that realistically the vast majority of us did not have family members or friends that died in the attack.

At a fundamental level this patriotic bond alone seems to make the majority of governments considerably more altruistic toward their citizens than a company would be towards their customers.

After all the leaders of government are also citizens with that bond of shared country and patriotism that they share with other citizens. In a company there is a much larger "us and them" divide between people in the company and people the company is selling to.

So in this light the grandparent's response of "We the People" though short is pretty meaningful and accurate. Governments tend to have interest in their citizens because of this patriotic bond which says that both the leaders and the ordinary citizens are "We the People".