I can see it running many games in "very good" frame rates and quality. But the economics don't make sense for Google if it tries to match the true high end PC configs. Once RDR2 is at 60fps, there will be other games pushing the envelope that won't be at 60fps on Stadia. Same applies to other consoles, of course... I'm saying that PC Gaming will still allow premium experiences for a while.
Either you buy a decent gaming PC and use it personally a few hours a week, or Google buys a decent gaming PC and uses it ~50 hours per week across ~10 users on average.
Google can probably also utilize that gaming PC during the other 118 hours of the week with batch jobs, indexing, etc. Your PC will just be idle and depreciating at 3am.
Not necessarily if you factor in some sort of impact for the slightly degraded experience they'll be offering you. You and Google may buy the same gaming pc and clearly they'll have lower costs, but that doesn't mean that your experience playing locally on that machine is the same as the experience of a streamed game on that machine. To compare apples to apples you'd have to compare the kind of machine you'd need to replicate the streamed experience, and that would very likely be a cheaper computer, so it's really an empirical question.
The high end PC customer can keep upgrading frequently, while Google will need to upgrade their entire data center to offer the top experience every few months. They will settle for a reasonable good/great experience for their user base, while the High end PC owner will always be above the Stadia standard setup.
So it's not that Google's cost is higher than the high end PC owner, it's just that the high end PC owner is willing to throw more money at it to stay on top compare to what Google is willing to throw at its entire user base.
Console hardware is vastly underpowered compared to PCs and yet frequently competes with mid-tier graphics cards in terms of performance and graphics quality.
The reason is that game devs are able to optimize their games specifically for the GPUs in the console hardware. Google is presumably betting that if they get enough market share, devs will start to optimize for _their_ hardware, and reap similar rewards.
