Can Mosaic still be made on non-ladder expac or? And what about rotw non-ladder?

I know it's disabled on ladder but I just saw someone trying to sell a 15/15/15 3ps claw at an absurd price saying "old roll never coming back" so I didn't know if they weren't able to be made now or what?

Yes.

i tried telling that guy hes wrong lol he wont listen. can still make