if MLB renews streaming rights with RSNs on the terms they have been, fox sports net is worth a lot more than if they decline to renew and produce the content on their own
The current terms of the agreements just allowed them to allow authenticated access to anyone with a cable subscription. That doesn't really allow a whole lot of value, as they can't really monetize the streams. It's not like the networks can cut a deal with Amazon or someone else wanting to making a splash in the sports streaming world.
I don't think MLB really wants to buy the FOX RSNs. I'm not sure what they're motivation for being involved is. These channels likely have a few years of profitability left, and then subscriber losses will put them upside-down against the long term rights agreements they have with the teams. My guess is MLB is concerned that some investment company is going to buy them on the cheap, siphon of the profits while they can and let them go bust.
MLB seems very aware that the RSN bubble is going to pop and when it does, it is going to hurt some teams a lot more than others depending on when rights agreements expire/networks go under/etc. It seems to me they have a plan to use streaming to maybe help soften that blow, and maybe even out the playing field in terms of local media money.
Hopefully their plan is in market mlb.tv for all, and they are buying the the fox networks so there's no resistance from 14 of the teams rights providers. Probably just wishful thinking though.