Cross compatibility

Yes, the Platforms will not be Cross-compatible.

already exists in certain games, with the passage of time should increase that list

Microsoft already allows this. Developers have to allow it for their game though so it's up to them to put it in the game.

Im pretty sure alot of future games will have cross compatibility there are plenty of games already that offer this like sea of thieves, dauntless, and minion masters

Are we going to get cross compatibility on PC so we can play with console players?

Depends on the game, and then depends on the console (assuming we are talking strictly xbox one). THere is more support for cross play then there has been. But it really depends many times on title and what the developer is willing to support.