Computer upgrades amortize pretty well. Over the last 8 years I've made 2 upgrades to my computer: A new SSD ($100 for 1TB) and a new GPU which is overkill for many purposes (~600 for a GTX1080). That setup can play many games at higher than 60fps, which beats the hypothetical max of Stadia (and I'll believe "4k at 60fps" when I see it— the Project Stream demo seemed to have a much lower framerate than that while still having noticeable artifacts on a 1440p monitor). Compared to that, $30 a month for streaming (if that's the price) seems as predatory as those companies that let you rent-to-own a TV. Although I'm not a fan of renting games vs owning.