It is, but it's also going to run the same games the XboSX will, meaning it'll also play all the same multiplatform stuff the PS5 will have. No, it won't be as pretty and it won't play in 4K, but it'll cost you a couple hundred dollars less.
Probably because Microsoft threw the ****ing gauntlet down with that $300 price tag for the Xbox Series S. That's a heck of a price tag for a next generation console, and I don't think either model of Playstation 5 is able to match it.
Speaking specifically of the PS4, did those revisions really make much of a difference? I know the slim reduced form factor, but the Pro seemed like a bit of a luxury upgrade.