There are still formats where you see a wide variety of decks, but T2 play normally involves picking one of maybe 5 or 6 viable options.
With MTG, even if I went down to my local card shop for Friday Night Magic, there would be enough people there with netdecks to ensure that creative attempts at deck building don't succeed very often.
In a local chess tournament, the level of play isn't even close to being that standardized. Most of the local chess clubs I've been to don't even have more than one or two rated players.
The difference is pretty simple. In MTG, anyone with 200 bucks can buy a world class T2 deck and learn to play it reasonably well in just a few hours. On the other hand, highly standardized play in chess usually only occurs after years of intense study.
There is, however, an easy way to fix MTG's shortcomings. I just play casual/peasant/other unorthodox formats. It makes things more interesting and its cheaper.
So, I spend my weekends putting on a black uniform and working as a tournament judge at professional-level Magic events. And... maybe you're right that someone could do well at a local FNM this way. But at any sort of serious competitive level (even at the Pro Tour Qualifier level), your assertion just doesn't hold up.
You can see this in tournament results, by the way. Card availability is basically only an issue for casual/FNM play. At any sort of real competitive tournament, the field is made up of players who have access to the cards they want, and the winner is determined by a combination of preparation and skill.
Most importantly, you can see this in results from Limited formats (where players build decks using cards opened on-site from standard booster packs, which are unpredictable enough to constitute a random per-player card pool). Though there are certainly "Limited specialist" players, for the most part you will see similar lists of names among the top finishers in both Limited and Constructed formats, which drives home the point in a frankly undeniable way.
Limited is a great format that I'm glad you mentioned. Anything involving a draft is going to be pretty creative.
Just to be clear, I'm not saying that MTG is inferior to chess. I like both games equally well.
Beyond the decks/openings analogy though, I'm not sure Magic and chess really compare well.
I think the most interesting distinction is in innovators vs. honers; Gerry Thompson is now out of the game at the professional level, but he was one of the greatest honers who ever played the game. Gerry was not known for coming up with new deck ideas, and in fact the few times he tried it he did horribly. But his ability to analyze the tournament landscape week to week, and make the perfect couple of tweaks to existing deck shells, was unmatched.
In some ways, the printing press ruined games like chess. I still like to play, but the widespread availability of opening books stifles creativity.
(I have a lot of experience with MtG, and a fair bit with chess, and this is my go-to analogy. I could also probably write a lot more on how the "netdeck" attitude signals someone is missing out on an unbelievable amount of strategic depth, but that's for another day)
It has two big downsides, the main one for me is that it's extremely expensive (a brand new console + collection of titles is equivalent in price to owning a couple of top tier decks).
The other one is that it's seen as uncool or childish or nerdish. I'd rather not mention it in workplaces anymore.
That said, yeah, building decks playing the metagame is very rewarding intellectually :) and having games 24/7 on Magic Online is great.
Not like Go, don't you think? (I do, been playing go for 10 years already)