Okay, so this might be my first post on this forum, so I may not have the credibility of some, but I just hate to see people going on and on when they're dead wrong:
I don't have to go check and familiarize myself with anyone. I _am_ a manager at, well, not best buy but an audio/video store nonetheless.
Did it ever occur to you that the reason you could be given a lot of "free" stuff, is because the markup on the stuff you were _given_ is much, much higher than on TV's? The reason he could give you all that stuff, isn't due to high markup on the tv, but because dealer cost on all that stuff is so low. The store might be better off giving you 1000$ worth of gear, than by giving you a 500$ discount.
Markups on cables, speakers, well - basically any audio stuff in the store, will be higher than on the tv. Yes, the markup on a TV is higher than it usually is on computers etc, at least at list price (but who pays list of anything _other_ than MAC stuff anyway??). However, there's a point here that you are completely missing: It's not about what markup the store has. It's about what markup the manufacturer has. The thing that has made Apple a roaring succes business-wise, is the fact that they like none other has succeeded in having a fairly high margin themselves, while allowing very low margin to the stores. The TV market is completely different. So, yes, store margins on tv's are higher than on Mac's (but nowhere near the highest in the store), but Apple's margin as a manufacturer would be much lower than what they're used to, if they went into the TV market, at least if they want to be competitive.
Of course, this is just my judgement, but you wanted a store manager to chime in, so there you go.