I don't really even buy the "we couldn't make Street Fighter V without Sony's money!" excuse.
Street Fighter IV was not some small niche seller, it sold like freaking 8+ million copies. Gimme a break Capcom. That's enough to finance Street Fighter V, VI, VII, VIII, and IX. Get outta here with that bullshit.
They thought Switch would bomb this generation and that they might as well put their money all in on Sony and get some exclusivity perks for it.
What they didn't realize at the time was Nintendo wasn't dead and that their PS4 endeavors would sell far less than they could have imagined.
The rumor/leak for Monster Hunter World on PS4 said basically as much ... Capcom started to panic after realizing the MH deal they made with Sony was probably a big mistake (after SFV bombed).
Sony's vision for the PS4 in Japan likely was if they could convince developers to back them fully, maybe just maybe they could bring back the home console market in Japan ala the PS2 days .... and Capcom likely got suckered into believing that vision. But it hasn't materialized ... PS4 is just another PS3 in Japan, OK sales, nothing special, and companies like Capcom that drank that Sony kool-aid are now paying the price.
Fortunately for Capcom they have a built-in "bail out" plan which is Monster Hunter 5 Switch. Capcom will never admit it, but that's the real reason MHW is not called MH5. It was an escape out just in case, especailly after the Street Fighter V debacle. Capcom has already destroyed one of their major IP this gen, they can't afford to do it to a second.