That’s not exactly what parent was saying. They were saying, afaict, if an org is struggling with retention then each successive generation will be worse at affecting change. They aren’t saying anything about individuals themselves who switch jobs often.

But about your point I think it can depend greatly. Personally I switched jobs many times but have so far kept in the same field and my knowledge has compounded and I have never dealt behind. In fact sometimes I feel the opposite, some coworkers who have less diverse experience have less to offer.