Steemit itself won't. That would add far too much space to the blocks. Though view.ly is a project that some community members are working on using IPFS (Interplanetary File System) to try to implement a video hosting system we can embed into steemit.

Steem will not be embedding media other than text into the blocks as far as I know it. Yet, we can build decentralized services that work the same.

So it won't likely be steemit that solves this but you'll still be able to use what people come up with on steemit.

I would like to see them working with view.ly, and bitchute which are both working on decentralized video services. View.LY is trying to do this with IPFS. Bitchute is trying to do this using torrents.