I think several trends are in play here, and they are sometimes pulling in opposite directions.
First among them is likely the effects of aging on the "baby boom" generation. We can, and do,watch our diets, but things stil get out of whack. When that happens, a load of warm soap and water is quick, effective, leaves you feeling better, and more acceptable at a somewhat more advanced age.
Next, the need for an inexpensive solution. I don't want to digress into politics, but I really believe that the long summer of the petroleum-fueled "consumer/disposable society" will become too extensive to sustain.
TV advertising was tried for disposable enemas as early as the mid-1970's; you don't have to spend too much time surfing channels to learn that there aren't many taboos out there any more. But enema or rubber goods ads for the bouncy, perky, oh-so-trendy suburbanites on the Weather Channel? .... I don't think so.
And Political Correctness, the "cult of the child" and the less-stable family structure of the present day lead me to believe we'll not return to the time when enema bags hung in plain view in many homes.
Overall, though, things seem to be moving in favor of a modest revival of "traditional" enema use and acceptance.