Check out what Adobe is doing to there own customers who own the CS5 and CS 5.5 suites:
http://www.computerworld.com/s/article/ ... onomyId=85
on Adobe: Pay upgrade price to patch critical bugs last week
This gos back even further.....many,. "many" moons ago there was a program called FontMonger. It was a font editing tool that ran circles around anything that Adobe had and for a small fraction of the cost.
Adobe couldn't put them out of business any other way, so they bought the company, and let all support (which consisted only of acknowledging that they now owned the product) die out unannounced within a year.