it doesn't have to do with recency bias. Also, it's not more stark the lower you go. Most kids don't get into competitive swimming until 10-11 or so. Competitive gymnasts often end at 14. Additionally, most competitive swimmers in youth are at most just casual. There is very little "casual" competitive gymnastics. Competitive swimming goes longer into adulthood as your body can handle it a lot better than gymnastics long term. Gymnastics has the highest injury rate of any youth sport. It's one of the reasons gymnastics will always be more revered as needing more overall athleticism.

I find it funny that you seem to be arguing this because you as a swimmer thinks swimming is being disrespected. Talk about bias. I wrestled in high school. No one talks about that sport really, even though the athleticism needed is off the charts. It's just how it is.