There are probably still going to be millions of Win 7 users who don't switch to Win 10 by 2020 tax season, and large and small business users using Enterprise versions can pay to extend the Win 7 support through the MicroSoft program "Extended Security Update program."
So if Intuit goes through with their announced plan to no longer make a Win 7 version for 2020 tax year, they are going to lose that business or have it shift to an on-line TurboTax version, like users of Linux do.
QuickBooks 2020 will also run on Win 7 as long as one has it up to date (Service Pack 1) according to the Intuit system requirements page, but there it says "only supported until January 2020" whatever that means.
