So a lot of the pilots won't change because piston engines is sort of an identity to general aviation?
The "older" crowd tends to have a very strong allegiance to what they trained with. It's much the same as how someone who was in the military prior to the introduction of the M-16 tends to have a less rosy assessment of it than someone who has known nothing else. However, economics is the bigger issue. Since most of us pay out of our own pockets to fly, you're going to have to show a major benefit in terms of:
-Fuel economy
-Cost of maintenance
-Frequency of maintenance (what's called "time between overhaul")
-Cost of acquisition
...for most pilots to consider switching to a similar

Also, the need to get a supplemental type certificate (STC) for commercially built aircraft to switch out the engine is a big issue for those flying Cessnas, Pipers, Beechcrafts, Cirri, etc. Establishing an STC is not cheap so.....

Do you think that can change
If someone were to meet all or even most of the above criteria, conceivably yes, especially among those of us who are more attracted towards the "business" end of flying than those of us who just like to smash bugs and bore holes in the sky on the weekends. However, do I think it is likely to happen? No, not really. There will always be those who are the reciprocating engine crowd and then there will be those of us who are the "kerosene club". I happen to fall into the latter since the design I am working on currently will have a turboprop engine.