I think that's wishful thinking :-)
MLS can do this because they probably didn't have a lot of others clammering at the door for the rights in this way. For the most part, leagues have worked out that dividing their rights up into packages generates them more revenue than selling them in their entirety to one provider. The NFL is the exemplar of this selling games to all the major networks, ESPN and Amazon, and also having the Sunday Ticket package, and Red Zone, and whatever they offer in app, and and and...
If they reckoned they could get more from a single vendor then they might well do that. (Obviously NFL deals are looonnnngggg so it'll be a while before we see if this is the case).
[As an aside, a new deal has just been done for Indian Premier League cricket rights, and they've just split broadcast TV and digital streaming rights into separate packages. Each was as valuable as the other, and the total deal is about $6bn for three years - far fewer fixtures too since the IPL runs across two months. The BCCI who run IPL took a leaf out of US leagues' books and introduced a third package of good games that the Viacom18 (the winning streaming company) also bought to ensure they had exclusivity for streaming. Hotstar, owned by Disney got the TV-only deal, which could massively impact Disney's "Disney+" streaming numbers when everything pans out, since Indian cricket fans contributed 50m or 36% of their subscriber base. ]
Also, leagues do think about their visibility. If you go exclusively on a single platform, you might well be out of sight and therefore out of mind for a lot of "average" fans who aren't quite as dedicated. I believe the MLS deal leaves room for some non-exclusive games in places like Fox, ESPN and Univision , although no deal has yet been announced. I would think that for a relatively young league, they'd want the kind of exposure those channels would give them. Going Apple exclusive probably doesn't help continue the league's growth.
This is a US only deal. MLS is shown across a couple of channels here in the UK, but it's fair to say that it's not remotely as interesting to European soccer fans as EPL, La Liga, Serie A etc.