Yes, of course it takes more time!
But I add another factor: the top players take care of each other. And there are players that nobody wants to face, so when those players connect, many disappear or do not ask for battle.
Also, once you reached rank 1, to the dark skull (ancestral symbol of regeneration), why do you want to continue playing? You will get the same reward as any other rank 1. Do you want to compete for the first place? You will have to compete with a player who carries more OP in his energy mechs than a field of stars …
Simple, you stay where you are, don´t play and watch: when there is no pro connected can u do your 5 daily battles.