I think Gmail was great initially because of dogfooding. Right now, the incentives are different, and it's more about releasing new stuff. And we can see how that worked with the Google Chat saga.

Lots of other Google products suffer from similar issues because of an apparent lack of dogfooding. I bought a Pixel phone not so long ago and I had to install all updates, one by one, to bring it to the latest Android version. It took several days.