Why F1 went away from Turbos--it was thought at the time that 1000 HP (race 1400 HP qualifying) was becoming dangerous. It was very difficult for tires of that era from lasting a whole race {hint: no pit stops in F1 of that era}
After the 1.5 litre turbo era, F1 went to 3.5 litre naturally asperated engines (any cylinder count). These started out as 13,000 RPM monsters with 650 HP and ended up 2 years later with 850 HP at 17,000. And for the same reason as above the displacement was dropped.
After the 3.5 litre era, F1 went to a 3.0 litre V10 naturally asperated engine formula. These things started at 700 HP and quickly grew to 800, then more slowly to the 940HP levels of last year. Then for the same reasons as before displacement was dropped.*
After the 3.0 litre V10s, we get 2.4 litre V8s with fixed bore centers and a fixed CoG point. These engines are expected to debut in the 800 HP range and get back to 900 HP within 3 years. The inherent balance of the V8s over the V10s solves the one axasperating issue with the V10s--imbalance. So, the 19,000 RPM limit of the V10s will not prevent the V8s from running upwards into the 23,000-24,000 RPM range--even with the fixed bore center of the V8s. If the engine boys can solve some friction issues, there is no reason a V8 engine with todays structural materials and current F1 rules cannot deliver 950 HP.
[*] in the middle of the 3.0 litre formula, they dropped slick tires and implemented groved tires to slow the cars down. Well that worked for exactly 2 races before the F1 boys were ahead of the pace of the previous years cars on the lesser tires.
The implementation of the 1 engine per race weekend slowed the developemnt of engine technology from the expected 950 HP in 2004 to only 900 HP in 2004.
The implementation of the 1 engine per 2 race weekend rule only prevented 1000 HP cars in 2005 (we only saw 940 HP levels and excelent longevity).
If anything, the longevity of these engines bodes well that sometime in the distant future automotive drivers can indeed experience 10,000+ automotive engines that meet emissions and 120,000 mile durability levels. There are already several 9,000 RPM engines** that meet EPA emissions and longevity.
[**] fuel cutoff not RedLine.