We've made a Mac and PC version of BiaB for almost 30 years, and plan to continue that.
The PC version has been significantly ahead of the Mac version, except for the last few years, where the Mac version has caught up. One indication that it has caught up, is the nature of the requests for the Mac version. Instead of talking about BiaB, they talk about other programs like PowerTracks or RealBand, which we don't make for Mac. That reads like progress to me, because we used to hear about missing features in the Band-in-a-Box Mac version, but we added them, and the programs are very close now.
And the BIAB Mac version is better in some respects (driver latency and plugin support for examples ) and the musical content is and has always been identical (which seems like the most important point to me).