I think you're misunderstanding the above comment. Buying a perpetual license for a particular version (or set of versions), then in the future optionally paying a fee for a new major version not covered by that license is extremely common and imo the most fair model for both creator and customer. If you never buy an upgrade or newer version, the version you own continues to work the same way it always has. You just don't get the newest updates for free.
thfuran|1 year ago