It’s not even so simple to swap an IAE engine with another IAE. It was either the dfw engine fail or Ord cowling unlatch event that grounded an old 319 several years ago.

Turned out the pylon was damaged and there were no pylons available from that era. Something about this older pylon was different.

I think they had to find a used one from the bone yard to get the airplane flying again.

Try swapping from lycoming to continental engines in a GA airplane and let me know how cost effective it is.