I don't expect big changes over time in the number of people with intense interests in ABDL. Most of us developed those interests either in childhood or in our teenage years. We were too young to appreciate the level of social acceptance or lack of acceptance for ABDL. So changes in social acceptance of ABDL won't affect the number of ABDLs very much. (Of course it would have a big effect on our quality of life!)
Some 2008 data on when people in the online ABDL community got interested in ABDL:
What could affect the number of ABDLs is a change in typical childhood experiences. In the United States, the typical experience of elementary school age children has changed a lot during my lifetime. Kids today get a lot more adult supervision and a lot more screen time than my generation had. My sense is that the typical experience of early childhood hasn't changed all that much since the 1980s. So that's another reason to expect the number of ABDLs to stay the same over time.
Anecdotally, I seem to be meeting more people recently who got seriously interested in ABDL as adults. Maybe that's a consequence of greater social awareness and acceptance. Or maybe it's because I've gotten older, and the ABDLs I'm meeting now are mostly over 30, and people who develop an interest in ABDL after age 18 tend to develop that interest after age 30. Or maybe I'm perceiving a pattern that's not real.
There has
definitely been an increase in social acceptance in the kink community (at least the gay kink community). Leather bars and events are having organized events for ABDLs. That wasn't happening fifteen years ago.
In the broader society, I think there will be increased social awareness and acceptance of kinks of all kinds, though there will be moments of backlash from reactionary prudes. I think there will also be increased social awareness and acceptance of asexuality. That said, I also expect increased social judgment about the environmental impacts of people's behavior. Thirty years from now, ABDLs will probably face less social judgment based on old-fashioned notions of purity and more social judgment about the environmental impact of wearing diapers without a medical need.
