There has not been a single commit in almost a year but there are 303 open issues (granted there are a few duplicates there 
)
Is this extension finished?
The more interesting thing is the platformio-core
That’s where things happens.
The last commit was 5 days ago - so every thing should be fine 
I know, but there also is not much happening according to the release notes, compared to some time ago…
Even more important than the platformio core are of course the platforms themselves.
So you need to look at the development of the relevant platform.
bro platformio ide simply does not appear to install in vs code extensions, also in browser it is no longer availible in marketplace