Lots of questions, but the main one is whether we have made any progress with these new toolchains and programming languages w/ respect to performance or robustness. And that may be unfair to ask of what is a genuinely useful tutorial.
I assume the point of these tutorials is not to show experts how to progress from the state of the art, but to show beginners how to get there. There are a few tutorials like this (build your own text editor, operating system, etc) and I think they are a great idea if done well.
The lemon parser generator is actually a delight to use if you're into that sort of thing. Paired with re2c you have a combination that rivals yacc/bison IMHO.
It’s much more ambitious/complete than the db presented in the tutorial.
If memory serves me correctly, it uses the same parser generator as SQLite, which may answer some your questions.