Not if you're a pro trying for a championship. There's a class of poor swimmers, but with awesome bike/run skills who clean up at the smaller races but who repeatedly flounder at the big races because the race gets away from them. Lionel Sanders, Sam Long, Joe Skipper, Sebastian Kienle, Cam Wurf.

The difference is at the big races there are group dynamics (notably a legal distance bike pack but also a swim pack) which don't form to the same degree in the small races, where a poor showing in one sport can be made up in another.

On the men's side, the last person to win Kona or the 70.3 world champs without making the front pack swim was Sebastian Kienle in 2014. The last person to have a decent chance was Lionel Sanders in 2017 (who came second in Kona).

If you're a pro and want to do well, you absolutely can't win big without being a top tier swimmer.