Agreed. So many artists, photographers and models used tumblr to showcase their work. It was also easy to link your blog to a .com with little to no webdev experience.
The only other social media network out there with a following that allows near the same level of expression is twitter and I have already seen posts from artists directing their followers there. But twitter is no real substitute to what tumblr offered.
I imagine tumblr's bandwidth costs are going to shrink exponentially.