The change has been in what online has done to the skill floor.When it was local only the expected skill level could stay low as crap players fought crap players with little inking as to what was happening in the wider world. Now I have no one locally to play and it as you yourself lay out online has made people aware enough of good play that to have any chance at all you need to do homework to be entry level. And yeah as they said above me here single play has been a huge part of SF even in the arcade days.
Fair enough. I was just pointing out that said "homework" and practice didn't mean hours a day as you initially implied. But it does mean the skill ceiling is higher than playing pure scrubs locally back in the day before online play, youtube videos and streams raised the bar some even at the lower tier.
And of course there has always been single player gamers who liked running through Arcade Mode repeatedly etc. And it is lame they don't have that there, though it sounds like the survival modes with all the options may be as (if not more) satisfying to some.
But SF has never had a huge single player focus like MKX with the living towers, Krypt and all of that. Hell, if the story mode in June is on par with MKX's (though I doubt it will be) SFV will end up with more single player content that most entries in the series, as long as they add in vs. cpu and some arcade mode eventually as well.
But it sounds like it's just a genre of gaming that may be moving away from you. Same with some FPS series. Devs have stated that it costs more to make the campaigns in those, when the real money is coming from people buying for the MP and buying map packs etc.
Fighting games will likely trend the same with the most lucrative customers being those who play the MP and buy most of the dlc characters etc. over the life of the game. If they can get that base large enough, it's then more financially viable to focus all efforts on making content for that crowd, and not the single player gamers who'll buy the game, play it for a bit, and then trade/sell it off (or keep it on the shelf) and never buy any DLC.
Just the nature of the industry, and the way things have changed/are changing. Hopefully there will remain some series like MK that still cater more to the single player crowd for those into that.