devtrackers.gg
Unity is pretty damn easy to port to any console. If they truly have the rights 100% then it's TFP's decision to not update (for whatever reason).
I think they are keeping silent because they just simply don't want to maintain 3 other versions of the game.
People are already upset at the amount of time A20 is taking, now imagine adding like 2x the work for the same result, it would be pretty bad...
Sure, an Alpha 20 port *could* be made in theory (It's not going to be, but this is theoretical), but what happens if/when Alpha 21 comes out? The game is not able to be updated yet again, and console players are once again stuck behind PC players.