This is precisely the point you seem to be missing. All those things you mentioned were similar big announcements back in their day, and they all have just died by fizzling. What should be setting this one apart?
Also, most of them released working code.
So I guess we shouldn’t be excited about that, either.
I think they could get away with it for a while because none of the competing implementation would readily steal Python’s darlings, namely NumPy/SciPy and Tensorflow. Now there is competition, and it can really push CPython away to being a niche “reference implementation”, thus we are seeing these twitches.
The track record of CPython core team in the last decade makes me very wary when it comes to bringing in such features. Ship it or it didn’t happen.
P. S. Microsoft once threw a large sum of money at Kenneth Reitz to work on Requests, anyone remembers how that story ended?
However, the first release will probably suck like asyncio or type hints did.
It will take time to become usable, but it's unlikely it won't happen.
Namely, that it’s absolutely not guaranteed to work.
Mypy was Jukka Lehtosalo's work, asyncio was fixed and extended by many.
So now he needs a project at Microsoft, he changed his mind (or had it changed under pressure) and this is the project. We'll see, I agree though that the first version will be underwhelming, the following versions will have a max speedup of 50% but will be celebrated at conferences and here.
If that is cause for excitement can be seen when a product is finished.
When you like a tech, knowing people are brewing improved perfs on it is kinky. On Python, the motto has always been "it's fast enough", "if you want perfs, don't use python", "C extensions will solve this", "we don't want to make the main implementation complicated", "python dynamism and GIL make it a hard problem", etc.
So in the python world, it's particularly big news, especially given that previous attempts (gilectomy, unladen swallow, first pyston...) all died.