Business BASIC was ported to mainstream PCs and other micros as the market for dedicated Business BASIC minicomputer systems waned. It still lives on today in the form of two dialects: ProvideX and BBj. And people are still writing/maintaining applications in it.
> In the 1980s, Business Basics were ported from their original proprietary environments to many Unix platforms, CP/M, and to DOS. In the 1990s, some Business Basics were ported to Linux and Windows, ... [https://en.wikipedia.org/wiki/Business_Basic]
Know where I might be able to find some of the earlier versions? The DOS and CP/M versions simply for the archival/historic value, but I'd love to play with the Linux version in particular, early Linux software is virtually impossible to find. Early Windows versions would certainly be fascinating as well.
After this experience I can easily see how someone could still be writing BASIC for a living in 2018, whether for standalone desktop apps or for web CGI, etc.