They are two products serving two populations, and it seems unlikely that their timelines will converge anytime soon. However, "not converging" doesn't translate to not sharing. There are obviously some things iOS that would be at the least nice to have in Mac OS (the app store being the one of discussion now), just as there are things in Mac OS that would be (or already have been scooped and are already) nice to have in iOS.
The problem for me is not convergence per see, I would not mind having features from an portable OS in the OS that I use in my laptop or workstation, the problem is the impression that since iOS devices came to exist OS X is becoming more irrelevant, I think this tweet summarizes the situation: http://twitter.com/iTod/status/27297928138#
I think if there's something to learn from Apple it is trying to take seemingly divergent markets or divergent goals and finding creative ways to reconcile them: form and function (look at the battery compartments in their wireless keyboard, for example), cost and sustainability, business and consumer markets, young and old.
That's how practically all decisions about the future are made.
Sure: don't buy it because of loyalty, that'd be stupid — but not buying it because of some worry about changes that the next version might have (and that Apple has said nothing about and that would be fraught with a number of technical and political difficulties anyway) is cutting off your nose to spite your face. And to use your phrase, it's voting with your dollars against something that's not harmful - if anything, it's sending a message to Apple that a certain group isn't going to buy their freedomful product anyway, so they might as well let those people use Linux/etc and turn the Mac into what you're afraid of.
The truth is for Apple this might as well be a great business decision. It is probably in their best interests, because their goal at the end of the day is to make as much money as possible. There is nothing wrong with that I just won't be buying it.
EDIT: And still is in the corporate market.