It's an interesting question... I agree that the move away from cable - and to streaming - threatens the revenue of cable content originators like ESPN. What I'm less clear on is what the revenue potential to MLB may be from subscriber-based streaming.
Consider: ESPN gets a cut - $7.21 per month, according to this article - from every consumer who subscribes to a cable tier that includes ESPN. A little money from each subscriber, but lots of subscribers. They use that money to bid for broadcast rights from MLB (and others).
Moving to a subscriber-based streaming model changes things in a couple of ways: first, fewer customers paying for access to MLB games, but higher subscription fees. As things stand now, ESPN gets a few bucks/month from everybody - whether they want ESPN or not, whether they watch sports or not. On a subscription mode, the customer base is smaller - it's only the consumers who actually want to watch ESPN (or MLB, if they go to direct subscription). But the fees - a consumer who actually wants to watch major-league baseball will be willing to pay substantially more than what he's paying now for ESPN. The consumer may not like the direct subscription fee, and may complain about it (in some future thread here!), but he'll pay it, because his alternative is to not watch the games. Think about it; if you're abandoning cable (because you want to, or because, as others cut the cord, cable's monthly charges go up to "make up the difference"), you will be willing to spend roughly what you're spending now, to get those programming streams that you actually want; if you're no longer paying for the stuff you never watch, you'll have more to spend on your priority channels. If one of them is ESPN, you'll pay $10/month, or $15/month. You can easily do that and still be ahead, if ESPN (and a couple of other sports channels) are all you want to pay for.
Is the net revenue to ESPN (or directly to MLB) higher, or lower, under the subscription model? I don't know - but I don't think it's obviously or necessarily lower. That depends on what percentage of the current customer base would pay for ESPN directly - and how much of their current cable outlay they would be willing to direct to ESPN (or to MLB directly). Then there are the customers like me (probably not a large group), who decline to pay for cable (because it's a bundle of garbage channels that I don't want to subsidize), but who would be willing (or more than willing!) to pay a monthly subscription fee to see televised MLB games.
Aside: I actually pay now, for mlb.tv; but because the Phillies are blacked out, I'm not willing to pay very much, per month. Lift the blackout, let me stream Phillies games live, and my willingness to pay goes up - not to the monthly cost of a middling Comcast or FIOS package, probably, but considerably higher than I'll pay for archived games only. If I know my dollars are going to MLB, rather than to... well, I won't list out cable channels herre, but I can think of several that I simply will not subsidize under any circumstances, because, IMHO, they're destructive in myriad ways... I'll happily build that into my entertainment budget. I'm an outlier - I think about what I'm paying for - but there will be other consumers who, for various reasons, will pay more for MLB games than they're paying ESPN (through their cable providers) now.
