There are several reasons why people don't actually use the Studio B when working with AE stuff, and why they will always complain about power spamming in the main AE area.
There are, obviously, going to be people who just don't know about it. The game lays it out for you in the tutorial arc on a silver platter, but a lot of people ignore the tutorial completely, and it's easy to miss that little door.
However, I imagine that the real reason most people don't use Studio B is because there's no mission entrance in there. A lot of the people you see standing around in the AE building are organizing or looking for teams, and for the purposes of actually running AE missions, Studio B is mostly useless.
It's fantastic for working on your missions in peace, (I use it all the time) but not so much when you're trying to organize people to run your... ahem, "rewards based mission arc".
The people standing around waiting to start an AE arc are always going to be stuck surrounded by people with shadowfall and steamy mist, and the Studio B doesn't solve that problem for them.
I don't think that power suppressing the entire building would be very good either, since people don't like having to re-apply all of their toggles after every mission. It would also prevent the use of travel powers (even hurdle, iirc), making moving around inside the AE building frustratingly slow, and would also prevent pre-buffing your team before entering a mission (most notably, the Fortune tarot power from the Magic Booster). Not a HUGE deal, but an inconvenience nonetheless.