Tosh, I generally agree with you. Looseleaf teas are often (usually) better quality, and in brewing looseleaf tea, you have much more control over the brewing process. That's how I prefer to drink it. But during the morning rush, a fairly good quality teabag (Mighty Leaf isn't bad, but I like Lupicia which I think is slightly fancier/higher grade) is much more convenient. I don't have the time most mornings to brew a carefully crafted pot of looseleaf tea, unfortunately.
I do think that someone who only drinks teabag tea is likely to miss out on much of the tea world has to offer. It'd be like drinking only boxed wine + two-buck chuck + maybe the occasional decent $10 bottle, and never experiencing the richness of the remainder of the wine world. But for some people, that works perfectly fine...