Re: "Google is well known for enthusing about projects and later abandoning them."
>> Their track record certainly discourages me from contributing or buying their products.
Indeed, this is exactly what came to my mind as well. The only things that have a chance to endure are what they acquire, everything else they do inhouse is retired, with terrible transition plans to whatever some Google exec power play has got.
Play music, Talk/Wave/Hangouts/Duo/Allo/Meet, Reader, Inbox, Trips, Wear OS
This idea of using the public as alpha testers has damaged their brand - it is difficult to invest in new Google services or ecosystems. The release date seems to be the countdown to closure. Change for change's sake, or sometimes for worse.
I suppose if this is just an OS, and not an ecosystem something might happen.