I think it will be a matter of maket forces and corporate bottom lines.
The 80hp 912UL is only for european market where there is a power restriction in some countries.
If the regs change the UL will disappear. Same for the last remaining, nearly orphaned 582 2-stroke.
The price difference between the 912 ULS and the 912is is smaller than it appears.
The 912is INCLUDES the Engine Mount frame that the ULS does not.
That closes the gap by another $1500, placing them within $1,600 of each other out the door.
Admittedly, the 912is requires a more expensive Glass Cockpit, but that is not necessarily a bad thing considering all that they bring with them.
Ultimately the aircraft manufacturers will likely drive the market.
They will not want to market both engines so the Newer and Better and all that, will win out.
I can see the 914 bowing out in favor of the 915, do we really need two sizes of Turbos?
Once you have made the turbo decision, cost is not a major consideration; Go Big or Go Home, rules the day!
The future will tell.