Comfort zone
Some don't look at either. Some just like being different. Not that they don't care about safety, but in aviation, even experimental, pilots assume or expect a certain level of safety, especially from a FWF package.
May be some pilots feel they can handle any situation, even loss of power. I am not discounting the severity of loss of power, but it's like riding a motorcycle, you have to check out some thoughts of safety and security when riding one. You still can get killed in a car, but some people accept more risk, whether real or precived. There is no doubt on a motorcycle, even with experience, leathers and a helmet, you are more exposed. I know a lot of careful experienced skilled motorcycle riders that got wiped out, to no fault of their own. As a old and wise philosopher once said, stuff happens.
The question is, does an experimental engine and installation expose you to more risk? Would detailed engineering assure you no tragedy will befall you? Will 2,000 hours on an engine by one owner make you feel better? If its a contest of service experience, the certified aircraft air-cooled direct drive engines are so far ahead, no other engine will catch up in out life time.
It's that new quantum leap into a now unknown technology that we are waiting for, a technology that will make all Lycs and TCM's obsolete overnight, with no question of reliability. This new technology will most likely not be in the form of another 4-stroke piston engine. We kind of have a better mouse trap, turbines, but they are not suitable for small GA planes, due to physics and economy. Turbines probably will never be practical for small privately owned and flown GA sport planes. We have maxed out existing technology. The rest is just more of the same, in a different form.
How will we know when this new technology in GA engines arrives (if ever)? We will know it when we see it. It's like going from rag-n-tube bi-planes to aluminum monocoque cantilever mono-wing planes, it's just better aerodynamically. (A Stearman is still awesome.) When jets hit the commercial market, DC8, B707, the piston planes days where numbered in commercial aviation. There was no doubt. Will Subaru's, Mazda's and Chevy V6's or V?'s ever rule the sky? Probably not. I am just worried GA will die out all together. As gas goes up, we will be looking back at the $100/barrel as the good old days.
If an experimental engine is flown under flight test conditions, with detailed instrumentation, under sever operations to some high water mark, that would impress me. However that would be an expensive and long term program. The service life and reliability of alternative engines is hard to nail down. Many are being flown normal or nominal conditions, quietly some where, but at this rate it's statistically insignificant. However at the same time 100,000's of hours are being logged by Lycs and TCM's.