Generally agree, but I don't think the situation is quite as bad as this, for two reasons. First, I agree that stated preferences can change drastically over time, but I suspect that actual preferences are more stable. Second, introspection is difficult and humans are not automatically strategic, so people are both unlikely to have a good grasp of their own preferences and unlikely to reliably take actions to satisfy even what they believe their preferences to be. Life changes that look like they're changing your preferences might just be life changes that help you get a better grasp of your existing preferences or get better ideas about how to satisfy them.
My guess is that the life changes that are most likely to change your actual preferences are those associated with biological mechanisms, e.g. puberty and the biological clock. The ones most likely to change your stated preferences might be those associated with substantial shifts in your peer group, e.g. going to college. Either way, these kinds of shifts both have the property that everyone else is going through them too, so at least they're not weird shifts.
Kawoomba, judging from my conversations with him, believes that stated preferences are all there is. When you convince someone they were wrong, their terminal values change. So naturally he views this prospect as rather more common, and undervalued.
A current article in Science reports on this study about how good people are at predicting what their future selves will be like. Not very good, apparently. Daniel Gilbert, a psychologist at Harvard, with other colleagues conducted several experiments online, in which 19,000 people were asked about such things as personality traits, preferences in music, etc., answering about the present, about themselves 10 years earlier, and about what they expected 10 years hence. More precisely, this not being a longitudinal study, people of any age X predicted less difference with their X+10 selves than people of age X+10 recollected of themselves at age X. The effect did not go away with increasing age: 58-year-olds still expected less change in the next 10 years than 68-year-olds reported in the last ten.
Gilbert and colleagues call this effect "the end of history illusion," because it suggests that people believe, consciously or not, that the present marks the point at which they've finally stopped changing.
"What these data suggest, and what scads of other data from our lab and others suggest, is that people really aren't very good at knowing who they're going to be and hence what they're going to want a decade from now," Gilbert says.
Someone suggests an alternative explanation:
Another possibility is that people "might well anticipate substantial change, yet not know how they would change, and thus, just predict the status quo"
An actionable moral:
"The single best way to make predictions about what you're going to want in the future isn't to imagine yourself in the future, … it's to look at other people who are in the very future you're imagining," [Gilbert] says.