My theory is that this has something to do with the average Googler's tenure lasting 3 years. With such a high turnover, the overwhelming majority of employees are probably much happier achieving the supposed glory of making something new rather than understanding and maintaining the old system.
Maybe another reason for the change is that, back in the Marissa Mayer days, hiring standards used to be much more brutal. Google was still reaping the rewards of bucking the trends of web portals jammed with ads, but eventually lost its confidence in nerd-driven products and instead began to imitate Apple, Facebook, and inexplicably, Microsoft...
My personal one is that they just can't stop tweaking. It's not like there aren't some fundamental improvements with a lot of their services but everything needs to get touched and then it ends up like that car Homer tries to design in that episode of The Simpsons.
I know that you're supposed to constantly iterate and try and improve performance, design, etc in software but is there anything in the general literature / case studies of 'improving' too much and degrading the core product(s)?
Not to mention that it's always funny to search for an issue on Google, find the links to the forum, see all the people that chime in with a similar issue, the few souls that try to help, then, as you scroll, the further desperate comments of "They don't care about us." Shouts in the wind.
Maybe another reason for the change is that, back in the Marissa Mayer days, hiring standards used to be much more brutal. Google was still reaping the rewards of bucking the trends of web portals jammed with ads, but eventually lost its confidence in nerd-driven products and instead began to imitate Apple, Facebook, and inexplicably, Microsoft...