This switch can be attributed to two things: the freedom that comes with iTunes' option to buy songs individually as well as full albums, and our generation's growing lack of attention span. It is rare at a college campus gathering to hear one song in its entirety, let alone an entire album. Also, we're impatient. We can't wait for our favorite artists to come out with new material, and they have recognized that.
This change is not necessarily good or bad. In fact, it seems to have more pros than cons for everyone involved, both the fans and the artists. In an interview with Rolling Stone, Billy Corgan of the Smashing Pumpkins said he was never comfortable with the album format because it felt forced. "It was obviously an economic decision made by others and not an artistic decision made by creators." He also points out, "It can be draining to record 15 songs over a six-month period." And as the same article article accurately points out, "Who cares, I'm only going to put a few songs on my iPod anyway."
-Erin