To me the advantage online music outlets (iTunes, Amazon, eMusic, etc.) have these days is how they don't have space limitations like brick and mortar music stores do. The immediacy of downloading is a convenience, but the fact they don't seem to have to restrict what they carry because they lack room in the bins (although they do have restrictions based on contracts with the labels, but that's legal, not physical) is the advantage. Not only does this allow for the obscure to be included with the popular, the back catalog and works of artists who have faded from the spotlight can still be found.
It's not that being middle-aged makes me dislike the contemporary stuff being released these days (I quite like the recent Wax Idols album, for example), but I cannot claim that the current scene appeals to me like what was the current scene twenty years ago. So what I am getting these days includes a reasonable amount of the material that I missed before, perhaps because I was too young (or not even born) at the time to have been into it (and never went through a phase) or maybe because I was too distracted by what I fancied at the time. With age I have not lost that inclination to keep finding songs that are new, but now some of those are actually quite old and merely new to my ears.