By the way on compatibility, Windows 7 is in fact supported by Microsoft in 2021-2023 (see: ESU / Extended Security Updates), yes, that means right now the system totally have security updates.

Supporting a system for free where you have to pay for support by the manufacturer is a No-Win situation.

We don't do it either. Also the design software we write plugins for doesn't do it. None of the big software manufacturers do it. No, in order to use our latest software version, we demand our customers to have up to date systems.
If they have old ones, they can use them of course, but they do so at their own risk.

"Supporting for free" is not "for free," is "for income," since the customers in question do bring revenue for your support, otherwise they will not use your software. A Win-Win situation.

Also, "we" stands for who/what? If you are talking on behalf of the company, I think the people deserve to know the name and probably avoid such a company and its products if they want to, especially long-term. A customer has the right to choose a system or update at the pace they want to, while you have the interest to sell a service, be in servitude, and when you don't provide the service all what you achieve is losing money from the customers that could be yours; Instead the customers will go to somewhere where the people care or steal the older version of your software that you do not provide anymore, for example. I doubt the latter is what you or your company truly want.