This topic comes up in various forms fairly regularly. I think the latest iteration I saw was "Is a :49 in the 100 freestyle fast."

There are always people who have a stricter view of what constitutes exceptional and those views typically comes from inside the sport. I suppose the reason for that is a coach or athlete will encounter someone with no work ethic but supreme talent who achieves a :49 (or 16:30 5k) AND will also encounter someone who has "mediocre" talent but great work ethic who also achieves the standard. They will then conflate what they have seen and conclude, hey, anyone can do it. I still maintain that a :49 is exceptional to the degree that it is something only thousands do out of hundreds of thousands. But I can see the other side of that argument.

But a 16:30 5k... come on. That is exceptional. The BIG difference between running and swimming is that, for the most part, anyone who CAN run a 16:30 does it. Every kid runs, the good ones get noticed and end up being...runners. You give me a 100 freshman boys who can swim one lap of freestyle competently but otherwise have no competitive swim background. You give me 4 years to work with them, I bet I can squeeze a handful of :49 100 freestylers out of the group. But if we tried that to produce 16:30 5k runners out of that group you might not get any.