A good LBS does a lot more than order and install parts. A good shop will lead group rides that help you get to know other riders and will shoe beginners potential places to ride. They'll offer trail beta for trails you don't necessarily know about. They'll maintain existing trails as well as develop new ones. They'll sponsor races, or at the very least, have some presence at races. They'll act as an advocate for cyclist-related community issues. They may even sponsor a grassroots team. Not all shops do all of those things, but if yours is one that does, consider yourself lucky and support the shop.

Plus if the LBS went out of business, then I'd have to buy tubes and Gu and things like that online. And I don't know what I'd do if I needed to have something installed that I don't have tools for. I'd have to buy my own BB tool and headset press, I guess.

And you'd go from paying $6/tube down to paying $2.50/tube.

3/3 LBS's I've dealt with were litterally dripping with arrogance, price inflation and "you're not buying a madone so the time I give you will be proportional to the fraction of the cost of your item to the madone" even when I was the only customer in the shop.

That said I did get great customer service and knowledgeable advice from REI; so the next time I live near one it'll be my LBS of sorts.

I've never paid $6 for a tube.

Of all the "bike shops" I've dealt with REI comes closest to this description.