"As many of you know, our original intention was to maintain .NET Reflector as a free tool. But, after two-and-a-half years of providing it without charge, we realized that we could not make the free model work. We know that this will cause pain for some people in the .NET community, and we apologize for the change in policy.
As a commercial company, we need to charge at least a nominal amount to keep .NET Reflector up-to-date and relevant. Without revenue coming in, we cannot dedicate a team of developers to ensure that Reflector remains a valuable part of .NET developers’ toolboxes."
They gave it a shot, for 2.5 years, and it didn't work. It's hard to fault them. Consider how ridiculously low $35 is for any tool of this sort, I don't think this is some money grubbing effort on Red-Gate's part.