So, basically, your whole point is to compare sales and public recognition of a brand ?
Competitive-wise, SF has the upper hand against MK. SF2T, SFA3, SF3S were played for years and still appear at some big tournaments. The only thing I know about the competitive scene of MK is about MK2, MK3 and MK9. Never heard anything about competitive scene of MK4 to MK8.
Regarding the actual games, SF and MK were always too different from each other. I always prefered SF gameplay and that's why I think the games are better, since gameplay is king in fighting games.
On the other hand, MK has been doing a great job on single-player content, especially on the story mode side and other bonus, such as the crypt and the towers. Last game from Capcom, that I remember, that had something close to it was SFA3 on the PSP.
Capcom took notice from what MK9 did, so I expect something from them in SF V. Street Fighter story is good (I like it, based on what I read from comics), but it needs to be much better told.