But whatever. If you were in the business of providing aircraft financing, would you fund a life extension of an old airframe or a new build?
You are talking corporate financing here, whether you get the funding is based on your business case, security and ability to repay. The interest will be based on the risk, that is all. You can get financing for just about any crazy idea, upgrading old machinery for continued viable operation is a fairly safe bet in industry and is done all the time.
I think the 2000 hp powerplant you want is still years away, from the ultimate PT6 or GE 93 for a straight upgrade.
There is already a better version of the CT-7 available, just not worth the swap over fees. As with everything it's a matter of what is available, at what cost in what numbers, we are talking a large business here not retrofitting a Cessna. Anyone familiar with whats going on with Rex and Link SAABs know you can rip out whats inside and replace it, the outside is just an aluminium and composite tube with some wings attached. The original SAAB was actually designed to take either GE or PW engines, however no operators accepted the PW option as it was deemed too new and non reliability proven.