Because xyz-as-a-service is anti-consumer. Unless you've been under a rock the past decade, there are many flaws with the model when it comes to consumers. It's great for business. Terrible for the user. As-a-service puts the consumer at the mercy of a company. Along with their privacy data. Steam at least is setup in a way where if they were to end, the games you have can be downloaded and unlocked. Just make sure to back it up. Stadia isn't setup for anything like that at all. If google put Reader out to pasture, something that cost them jack-dick-all to keep running, something as expensive to maintain as Stadia when it flops... "Oh, sorry, it didn't work out. Sucks for all of you."
Just because you can't see how a trap will be sprung, doesn't mean the trap doesn't exist. This will bite people in the ass a year or two down the road. Then everyone will cry, "How could this happen? We need legislation to protect us!" No, you just need to be quit being a baby and start being an adult and understand that minor comfort and convenience can come at a heavy cost.