IMO< its due to well, side focus is easier for most to do, and in all honesty, I think more and more folks like MOVIE looking guns, with BIG optic's and lot's of buttons and levers and dials on them, to make them look like they do more than they do(just like rifles and shotguns, the fancier High tech looking the better so much focus on image anymore? and wanting attention for having things)
so, IMO< its about wants and the OEM"S tend to follow trends and make things that the majority WANT< over need!
as for higher power offerings, I think a LOT of the GUN folks are getting older and well, eye sight's failing, so maybe there wanting to make up for that with more powerful scopes
and then again, there is a big FAD going on with LONG range shooting, and folks are buying to pretend they will do so LOL
as we all know, most hunters NEVER shoot really far , so again, its a WANT over need deal for a lot of scope and rifle sales!
folks want to THINK they can by the skills to shoot far!, and OEM"S are making things folks THINK They need or WANT!
to cater to the sales demands!