I seem to recall the average figure was about 7000 hours per power failure.
In 2000 hours' flying I've had 3 power losses in-flight resulting in 2 successful forced landings and one where power was recovered (mechanical fuel pump failure - boost pump got me home). Probably more than my fare share.
It's part of the design and certification procedure that the higher the likelihood of one of these events, the more the aircraft has to be designed to make them survivable. Principally for single engine aircraft, this means a low stall speed making field landings reasonably possible. It's also an essential part of the training in SEPs that you practise and can safely execute a controlled glide to a suitable forced landing site. Failing to fly the aeroplane and maintain a safe speed and attitude is more likely to result in disaster than hitting obstacles in the landing run. There have been several cases where aircraft have hit trees without causing serious injury because the aircraft was stabilised at a sensible approach speed.
If you look at the fatal accident summaries for SEP aircraft, forced landings don't feature that much.