I have a lot of respect for him for doing such high quality game work, mostly or entirely on his own. But let's not pretend he's some highly-productive programmer who churns out groundbreaking software at some amazing pace. I reserve such praise for people like Fabrice Bellard, who not only builds amazing things, but has built a lot of amazing things.
Tinkering around with a new language is cool and impressive, but it doesn't make you a "productive" programmer. Managing a game studio is useful work, but it's not "productive programming". I agree that his two games are great, and it's impressive how they were built, but... so what? He spent three years on Braid and seven years on The Witness. Is it "productive" to spend ten years writing two games? Not saying he was wrong to spend his time as he did; that's entirely his choice, and I know I personally have appreciated the output of those ten years. But I think many programmers have done much more productive things than building two games in ten years. I'm honestly not trying to shit on Jonathan Blow, but I think the hero worship I see over him is just a bit much.
In fairness he's been juggling multiple projects at the same time over the "for years" period that you mention: the new programming language, one major engine and game in said language, new releases for Witness and Braid, a secret game project, plus managing a game studio on top.
Also the two games he released "so far" are pretty popular and pretty well received by the critics _and_ they're programmed from scratch.
I think you're being a little uncharitable to someone that probably spends 75% of their waking life doing work (or ranting).