The upgrade system was software company driven: created and offered by the software maker as a 'reward' and an incentive to continue the support, and in order to receive that reward, one would only need to show that he/she was a previous supporter of the company.

Allan,

I'm a bit more cynical than you. I believe that the upgrade pricing was an effort to keep folks from moving to the competition and not any kind of reward. When the competition is not existant, there is no longer any motivation to give up profit to prevent folks from moving.

I remember when you get Word prefect for a really good price if you simply sent to cover page of your MS Word documentation in with your order, they called it a competative upgrade.