Because I really don't like the idea of a media singularity, which seems to be Disney's goal. I prefer competition, with more films than fewer films out on the market.
Before I would have said that Disney is capable of buying up companies and just letting them still be their own thing, but Disney's influences on Marvel clearly show that they're not happy with just treating these new acquisitions the same as they would treat a subsidiary like Touchstone.
Wipe the deck clean. Disney's just going to get more and more commercialized anyways, canceling original features in favor of these live action remakes anyways. They already went ahead and canceled Gigantic, and they have nothing in the pipeline that isn't a sequel or remake as fa as I know.