Game streaming looks good in theory, the problem lies in the execution, the primary one being the ISPs.
Many, or most consumers, at least over here in the US, will not see a smooth experience with Stadia's service, unless internet plans are upgraded and made more affordable.
And if one has a decent to high end hardware setup already, moving to this streaming service would be a performance downgrade.
Plus - and this is likely a bigger issue than the ISPs - it's a digital service in which the consumer owns NONE of the products purchased. So should anything happen that causes said service to drop out, the users are left with NOTHING... save for a nice-sized hole in their bank accounts(the service isn't cheap).