The discussion is interesting, and the reasons many, as to the transition to chemicals/meds away from the various solutions of the past. Certainly, convenience and personal preferences are part of the equation.
I enjoy reading the old texts regarding enemas, douches, and the equipment for these. The Wayback Machine, Google Books, and other sources of these older written media sources are quite enlightening.
One of my favorite sources is in Google Books and the subset "newspaper articles". It's amazing that several physicians published columns regarding enemas, constipation, and other issues. Some took questions and published answers. There was obvious disagreement on all sides of the issue.
One thing is for sure, my mom and grandma followed those who advocated the simplicity of an enema, and the concerns about affecting the entire digestive system. Our family doctors hadn't shied away from prescribing an enema for a variety of issues. Cost was certainly a factor in my family and may well have influenced others. Dr. Spock may have convinced some moms that enemas could have a very negative influence on kids.
I hated my mom and maternal grandma, and enemas may have triggered many of those feelings. The crazy part is that I learned to really enjoy enemas and self-administered from 6 years of age. As an old fart, I've come to understand their reasoning although some other hangups drove me crazy.