So you're telling me..

[Xiaoki]

Unless ACT measurements are completely broken in kind of RDPS-classes, the only justified reason, why they lack behind, would be "easy to execute".

Ranged Physical DPS have low DPS because they can attack from away and do not have cast times like the Caster Magic DPS, so they can move and shoot.

It's not a good reason, especially with how mobility has changed over the years, but it is the reason.