One such critic is John Maynard Smith. He wrote a number of somewhat critical reviews of books dealing with cultural evolution. However, in 1999 he wrote:
I used to regard the meme as a fun idea - helpful in explaining to students that there can be more than one kind of replicator, and that all replicators evolve by natural selection - but not as an idea which could be used to do much serious work. Genes have clear rules of transmission (in sexual organisms, Mendel’s laws) whereas you can learn memes not only from parents, but from friends, books, films and so on. Consequently population genetics can generate precise, testable predictions, whereas it seemed to me difficult to make such predictions about memes. Susan Blackmore’s book, The Meme Machine, has gone some way to changing my mind. Perhaps we can make the meme idea do some work.
Another critic-turned-enthusiast was David Burbridge. I've documented his change of heart in an article titled David Burbridges meme turnaround.
When I got involved in popularizing memes and cultural evolution I made a confession video available with transcript here: My Memetic Misunderstandings. However such articles seem rare.
This essay starts out with the hypothesis that it is difficult for people to publicly admit that they were wrong. A more sinister explanation for the missing turnarounds on the topic is also possible: people don't change their minds on this issue and take their delusions to their grave with them. Some dead critics confirm that this happens some of the time: Steven J Gould apparently took his delusions about the topic with him when he departed from the world. I hope that this explanation is wrong. Scientists are supposed to be responsive in the face of evidence, not dogmatically attached to their previous views. "I was wrong" is something that scientists ought to be able to take pride in saying.