I understand, but if we make a plugin now and we spend a certain amount of time and money for R&D, then we market the plugin for then next 2 years, providing bug fixes and sometimes small feature updates, then we decide to upgrade the plugin and we ask you 3€ for the new features it's not a shame I think... the only issue is if you buy the plugin after a year and half we have released, but this is not our fault and to provide the new version we had adde costs for research and development.
If you buy any DAW now and in 6 months they release a new version you'll have to pay the upgrade fees, I don't see what's strange here...you are not forced to upgrade to new version if the ones you have still works fine
Saverio