no one used Google Stadia because the business model and service architecture made no sense for a new service and for a company that has a habit of abandoning project that aren't an immediate runaway success stories.
Google legitimately thought they can enter a brand new market, and treat it like they are already the largest player in it. They duped themselves by honestly believing that "this is not the gaming market, this the the Cloud Gaming market". They did get most of the "cloud gaming" enthusiasts on board. All 200 of them.
They weren't like XBox or Nvidia who just had to go to gaming companies and strike a deal or ask for permission to stream their existing games. They were a new "console", you needed to develop for stadia. They needed to pay millions to incentivize companies to put the effort to port their existing games to stadia. Those companies had no customer for the "stadia console" version of their game other than Google sine no one has a "stadia console" or any way otherwise to play that game.
Those tactics may work for Sony or Nintendo or _maybe_ Microsoft. But not for a nobody in the business that literally has no user-base, no games, no history. They had nothing, and tried to pull a "we're the leaders in this market we can do anything we want and everyone will have no option but to take it"
I wouldn't really say that for any of the new products that people actually wanted to use. Including Google Domains (even if it might not be an effective use of workforce for Alphabet).
No one used Google Stadia because Google kills things with little warning, which subsequently caused Google to kill Stadia.
Google will never be able to launch another product.