I think it’s a real stretch to say that shidduch and divorce problems are a result of kollel. Do you have any sort of control group to compare to, which is relatively free of these problems?
Kollel is a siman, not the sibah. As I’ve mentioned before, the root problem is the expectation/requirements for seminary in Israel. I’m not going to go through it again, read the prior threads on the topic.
As for a control population, chassidim or pre1990 yeshivos would work.