Making sure your product still works every 7-9 months and fixing issues requires selling a kidney now? This is an opportunity cost of being able to continue to make sales on the marketplace. As well as being relevant, at all, to users on new versions.
You don’t need to give one on one support, but you should probably have some form documentation (where relevant) and fix actual issues that are brought up. People will cling onto you for support for free because you helped them with a single issue on Discord. This isn’t unique to the marketplace, much like open hostility to the end user.