Since just about every other software company provides software that works on High Sierra and older versions of macOS (and not with different versions of their software for different versions of the operating system - but with a single version that runs on all of the versions of the operating system), either Intuit is wrong or the rest of the Macintosh development community is wrong. It is pretty obvious that it is Intuit who is wrong.
Independent of what Apple considers to be their currently supported versions of macOS, it is reasonable and desirable that Intuit generate software that runs on all versions of macOS that were released in the last nine years. Deciding to generate software that only runs on versions of macOS that Apple considers to be currently supported means that Intuit is abandoning customers who can't upgrade to a later version of the macOS. That is a foolish business decision.
