Power v heat waste losses
Slippery Pete, sir,
Saying that "the main reason for thermodynamic efficiency increase in high compression is reduced heat waste to the fluid" is, in my view, wrong. It is the "main reason" aspect of the statement that I quarrel with.
The primary reason for compressing the air is the enhanced power per unit time the engine can then produce; heat transference losses are also reduced it is true for the reasons you give but I submit that that it is a secondary (albeit welcome) effect of the compression.
With compressed air you have more oxygen molecules in the combustion chamber and you can burn more fuel per unit time. You release more energy to do useful work per unit time. The time dependence is critical.
The main reason is power but you are right in that, under high compression, the loss of heat this way is a smaller % of the process i.e. it helps but it's not the key driver.
If we really want to get obscure the parallel with Le Chateliers Principle when justifying running big pressures on systems that are making fewer moles of gas in production processes is a good one - you "notice" the drop in entropy less than at low pressures.
Yes yes there's a rate of reaction factor at elevated pressures too but let's not go there either!
I suspect we shall have to agree to differ short of doing a lot of sums in public.
CW