why the devs take the lazy way out on low lvl content scaling?

[Jeeqbit]

why as we go lower that current level content we lose skills.

Because you are doing... lower level content that is not designed to withstand level 90 abilities. With lower level players who don't have all your fancy level 90 abilities. If you don't like it, just do level 90 content.

as of lvl 90 any thing under lvl 60 is close to not playable

That isn't the least bit true.