Actually no. Uniform flat surface is tiring compared to a trail even in best shoes. Try walking 10 km on hardtop then compare to walking same distance on unpaved road.

For shoes we also went not too far: Merrel sandals basically replicate roman caliga with modern materials. And it's not like you can use even halfboots in mediterannean unless it's winter - it's just too hot.

Empirically, yes.

You seem to be equating flatness with surface hardness. Tarmac isn't unforgiving to walk on because it's flat, it's because it has no give.