Yep, that'S one of the few things riot actually puts **some **though into.
If renektons W was allowed vs towers, he's be absurd, he already always has lane priority and an easy time pushing people in, if he when could also delete towers as easily, shit would snowball even harder than it already does.
One could argue that Darius also is a lanebully, but not on the same level as renekton and unlike renekton he has no escapes, if he splipushes it's pretty easy to clopase on him, while renekton's double dash gives some decent escape potential.
Also, there is a difference between 130% total ad and 150-225% with some flat damage on top.
Nasus has a rather weak laneingphase, unless he maxes E which when means less Q stacks so less tower damage, and like darius he lacks any mobillity to escape a collaps.