bluskis
You appear to suggest that engines fail a lot more frequently than every 3k to 10k hours.
This cannot be right, if you think about it.
The TBO on most engines is of the order of 2k hours. It is a fact that most engines that come in for an overhaul are removed from a plane that is still in one piece and functional. They are not carted in on the back of a pick-up truck, surrounded by wreckage of a plane that had to do a forced landing.
Most planes, even flying school spamcans, spend most of their airborne time out of gliding range of an airfield.
So if the average life of an engine was say 1k hours, not only would there be a huge number of forced landings (of the order of every plane used for training ending up in a field every two years) but also not many engines would ever make TBO before they end up wrecked. At the very least, nearly every overhaul would involve a shock load inspection, which for a fact isn't the case.
For me, it is easy enough to see why some people have had bad experience with engines.
For a start, any statistically rare event, be it engine failures or rare diseases, are subject to clustering. So you can always dig up somebody who has done 10k hours and has had 10 failures.
Also there is a huge range of engines flying, in terms of condition, treatment by users, and maintenance standards. The average UK GA fleet age is 24 years, according to a CAA CofA inspector I spoke to. But this average conceals a huge standard deviation. A lot of planes are 50 years old. A very small % are brand new. Most training / self fly hire planes are 20-30 years old but they are looked at more often (Transport CofA) and don't get a chance to rust too much inside.
So there will be a big variation in engine reliability, with most of the factors being controllable by a careful operator. I bet you could say the same for accidents, too.
Regarding rafts, I spoke to a well established manufacturer selling various rafts including GA and (although they would say this) they claim at least 99% do work just fine - IF they are overhauled by the schedule, usually annually. In GA, few people carry rafts and those that do rarely overhaul them by the book - it costs about £100-£200 and there is no legal requirement to do it.