It depends on Google really. They have the resources to make a decent console but whether they'll actually so that is another question.

In 2 years time they'll be PS4 capable on paper but not in terms of output. There's no way the galaxy S9 will be able to handle Uncharted 4.

It wouldn't be a good idea. People who play Android games don't expect to pay much for their games and smartphones will never be powerful enough to even scathe the PS4/Xbox One, making a phone powerful enough to even come close to these systems will render it useless as a phone. Android isn't a system optimized for games, let alone a lot of android apps run in the Java Virtual Machine which, while ok for some games, won't really do for AAA devs.

I doubt you played games who look better than your ps3 on your smartphone