Fiber has been effectively cancelled; Google has been shopping it around to various telecoms since 2017 but because it's an overlay network and it's not very large, nobody wants the headache of trying to integrate it. Fiber was always an attempt to push broadband providers to update their networks to better support YouTube; Google was never going to throw down the $100B that it would have taken to be competitive. It was never designed for long-term viability because it didn't need to be to serve its purpose.
And I hate to admit, they're doing great. I recently tried some different search engines (DDG among others) and they just never give me results as accurate as Google does.