>>211504
Same reason why "reality shows" are so popular these days. It's much cheaper to film people doing what they already are doing than it is to hire actors, build sets, write scripts, etc. All you need for reality TV is a cameraman and some editing.
Anyway, as for "cost cutting cheats" in anime, you certainly see that in some titles but it's not prevalent everywhere. TV anime is usually low budget and as such it's filled with recycled shots and simplistic backgrounds. On the other hand, look at a big-budget title such as Ghost in the Shell or X and you won't see that sort of thing.
It's no different than movies or TV in the west--you've got a lot of lower-quality titles and some that really stand out.