A friend of mine who has his own bike shop, (granted it's a small one man operation), doesn't bother stocking any new bikes anymore, (he can order them in though), mainly because there's not enough margin in them for a small high street store v's online retailers. He doesn't have the space to pile them high and discount them as much as online, and he couldn't afford the hit if he then had to heavily discount unsold models the following year just to shift them.
He makes his money, (it's hard work though), doing repairs and fixing BSO's supplied by other places.
I used to fancy my own bike shop once upon a time, (and I wouldn't rule it out now but I'd need those 6 numbers to come up first), but seeing what my mates gone through in the last 10 years or so has put me right off the idea as a means of making a decent income TBH