It seems like he's not even sharing the code, which is unfortunate if Alacritty or others want to learn from this. I guess that's a personal choice, but is it in the spirit of fosstodon (the mastodon instance he's on.)?
My commitment to "FOSS" is not up for debate.
I've written in multiple places what it takes to get stuff that fast. If that isn't enough for any of those projects, I'm happy to take money in exchange for my time.