Does this mean that Google is basically using all their services like Stadia or Fiber to keep people's minds aware of their presence, essentially using these services as their own advertisement outreach while hoping they also return a profit on their own advertisement?
They're using those services to "grab eyeballs" and collect data for advertising. You don't need a ton of users to get enough data about a market via sampling. Stadia is pretty new but I don't see it sticking around for the long haul. Amazon (Twitch) and Microsoft are in a much better position in that market.
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.
Or as other vectors for advertising. Stadia store sells ad space to game companies. Google Home is a speaker capable of playing ads (or more subtly giving paid-for answers to questions) etc.
Yup, it's amazing, the number of places they can sell ad space, or use to collect data to improve targeting. The games you play and the platforms you play them on will definitely help fine tune ad targeting. It's just Google clawing deeper into your personal life.
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.
They're also a recruitment tool. It's much easier to convince people to join Google with the promise of working on cool new tech, instead of just micro-hyper-optimizing endless facets of ad placement.