PRICE!!!
That's hopefully the right answer for most people. I mean, if some of these setups were available for $500 or $250, or $100, then we would be recommending them all over the place. The problem for most of us, or at least for myself, is that their price to quality ratio is just ridiculous. For a number of years, it was also very difficult to find smaller speakers from major manufacturers at a reasonable price. So, if you wanted small speakers in a room, you went to Bose and called it a day. That's kind of silly considering how much 'hate' existed out there for their product, which was selling really well. Now, you can find decent stuff for a much better price from almost every major speaker manufacturer. Some nice Def Techs, or Canton, Focal, Yamaha, Polk and others all have 'small' 5.1 type speaker packages. My headache kicks in when they have pricing that is near what Bose charges.
Perhaps my next biggest headache/complaint/gripe, is that they have systems that are 100% proprietary. You can buy a $2,000 system from them that can't even accept a standard subwoofer because there is no LFE connection. You can't swap out the 5.1 speakers with something new because the base unit doesn't allow for it. Or (worse) you can't swap in a new A/V receiver because the speakers aren't designed to make standard speaker connections. So, if your HDMI is out of date, you toss the whole setup in the trash. Who wants to do that?
That said, their noise cancelling headphones are supposed to be pretty darn good and for the money are supposed to be pretty darn price competitive. It's been a while since I've read some reviews, but I have read multiple reviews on those things and shootouts where Bose regularly ranked up near the top for performance. But, N/C headphones and 'headphones' aren't the same thing. I would only get N/C headphones because of the noise cancelling part.
They do have some standard speakers, that are overpriced, but sound fine to some and who am I to argue with their money if they already spent it? Install them, hook them up, call it a day. I'm not in the mood to make someone feel bad, but I will try to help them avoid that buying decision up front if I can. Unfortunately, the other 99.9% rarely cares.