Tumblr may be a company. But it was also a community. Real relationships were made on there. I wasn't big on Tumblr but it meant the whole world to thousands of people growing up.
Verizon could make its decisions in the context of running a company, or in the context of running a community. They chose the former, because as a money machine they have no interest in spending capital to be the bearers of a meaningful online community which facilitates the formation of meaningful connections between people.