While not because of crossplay, but just the games being on PS360 period, yea, I've been thinking the PC version could be held back unnecessarily. If the PC version is the latest, and with SG the latest is likely to be better, the PS360 versions won't likely be seeing much play. People fell off the game once the patch was announced, so it's not a stretch to think they definitely aren't going to play on consoles when the superior version is available on PC.
That's not necessarily a bad thing. I think the FGC as a whole would be better off if the PC was the standard platform for fighters, or at the very least, not an afterthought. But the only way that's going to happen is if fighters start seeing a consistent release on PC.
I'm not sure that a ported release is really going to get that train moving, but it could, especially if the PC version is updated as much as I imagine Mike Z and crew would like it to be.
As for changing versions, I asked about it before the game was released, citing BB as an example of a game that let you roll back to previous versions, and I believe Ravi said that they didn't know how to do it.