Again, I'm not opposed to upgrade costs and will likely (maybe) do this one but I would rather see a model of constant development and releases, with no lulls in the middle of the year. No bizarro marketing philosophies or teasers, just plain reliability. The example of Purebasic was offered earlier. Such an approach provides some confidence that the user base will grow. As noted above, this market is not captive meaning that users can simply switch, impacting the entire community. The potential for silence in the middle of the year is the perfect time to lose clients - too much ambiguity. Or, as in the case with Adobe, users often choose every second upgrade cycle. For a small operation that can prove fatal. And, again, the community suffers as a whole.
Just my two cents.