Ignoring the fact that every change in BBCS2 will be in the balance patch of BBCS (lol fact checking), your logic is flawed - people ALWAYS prefer local gameplay. I hated netplaying MBAC (mostly because I lived far away), and if there had been an arcade I would've gone and played in a heartbeat. I think a lot of people probably feel similarly - I mean hell, there are people that play BBCS on arcade cabinets just because they prefer it, even though the game is out for a system and such. It's just easier - you don't have to have a good setup, you don't have to have a place to host, you don't have to bring your own stick, you just show up and play. It's also fun - it's a gathering, you're playing.
The thing is, they can't prevent a "PC Port" anyways, with the ability to just emulate the arcade console on the PC, but if they released a PC port, instead of just losing money on it, they'd make money on the fact that people want to play on their PCs. Additionally, you have to look at it from the point of view of people in Japan - they play a lot of arcade games there, and I don't think having a PC release will kill their arcade profits. Then take this into account - if they release a PC port, it doesn't have to be localized for American users - which costs them less money for a larger consumer group. I can see absolutely no downside to releasing a PC port of this game, because a Japanese player is still going to go to the arcades (as evidenced by the amount of BBCS played in arcades there, even with a console version with MORE features than the current arcade), and American players won't have arcade cabinets near them anyways - so if you get them buying the PC version, you've increased the amount of money you're making for minimal work, AND you've brought the game to another country which is currently lacking in MB.