You assume the new engine will just work.
Unfortunatley, the track record so far is that every release they break the engine just a little more. To the point you have to go and build from source after fixing things to get a working version…
And let’s not even get started on how Chaos performance went down 400% between the first released demo and the (at least prior to last patch) official release of .26. I suppose “it works”, even if a lot slower and more expensive than physx with the same settings. But that’s been exactly the same trend for anything they released the past 2 years.
including RTV, left unfinished. Procedural foliage, left unfinished. hair groom, labeled finished and crashing the editor. Etc. Could go on for days like that.