https://www.vox.com/2014/10/7/11631634/new-google-head-david...
A month earlier I'd suggested 4-5 years, earily on-mark:
https://web.archive.org/web/20190115022452/https://plus.goog...
(I'd made a few other predictions, but they were roughly in line with that. I insist it was a fluke.)
And it turns out that it was very nearly precisely five years later that the service folded.
This on what had been a "bet-the-company" effort in 2011:
https://www.zdnet.com/article/google-aims-to-subtract-users-...
It was the only true competitor to FB, it would've needed to steal more features from Facebook but with G+'s touch, but nothing happened for years, they lost the vision to topple FB.
Given the dissembling surrounding G+ from the very beginning, credibility of that rationale is ... low.
For consumers that's fine. They understand the situation and approach Google products with that knowledge. Stadia is a good example.
The people who should be most wary of this policy are Googlers who are looking for a team to join.
So taking that lens it's easy to see why so many new products are launched but then fall away and are killed, because the people involved can get their money and then move on to do other things. Also explains the constant user hostile redesigns of existing products.
To fix the reputation in this regard the internal reward structures would need to be changed so that building new things is the only way to get ahead.
Only building new shiny things from scratch and never having to support them? Doesn't sound like a bad deal.
Most people (certainly everyone I've ever worked with) need to have positive external input and feedback on the work they do to drive them forward, and if you're not getting that and the feedback is repeatedly "Meh, it'll just be killed in a few years" it would eventually start to impact your confidence and ability to do good work.