[jesstaa]

The trade off has changed over time as memory access has become a bigger and bigger bottleneck. But caring about this is still "premature optimisation".

The claim of 20x program performance difference is overblown. Compilers can often remove virtual function calls, JITs can also do it at runtime. Virtual function calls in a tight loop are slow but most of your program isn't in a tight loop and few programs have compute as a bottleneck.

Measure your program, find the tight loops in your program and optimise that small part of your program.