That would be my strategy as well. Making completely new design I suspect would be more costly, and they are to be used with a system that so far is still needing to prove itself regarding earnings power.
That's a real shame. People beat up on Leica because of their high prices and botique marketing, but they do occasionally make breakthrough products without concern for protecting other lines. Such as introducing the Q2 at 47mp when the SL remains at 24mp. Or when they introduced 3 new breakthrough cameras at once in Sept. 2009.
Nikon could have made the Z50 a real challenge to Fuji, but I suspect Fuji is breathing a sigh of relief right now.