G8r. In my opinion swimmers are drawn to triathlons because there are few events for adult swimmers and it seems like the next best choice in competition. Besides Masters sprint meets and a few lonely open water swims there isn't anything like they used to have in age group swimming as far as competition. SO they start triathlons. Most have little to no experience running for any length of time (because swimming is a very demanding and selfish sport, they find themselves constantly back in the water), similarly, most have little to no experience biking, especially on a road bike. If they do get into triathlons most are doing it with mountain bikes for a while because getting a road bike is both expensive and "too serious" lol. It means investing in another sport, and as it is, swimming can be expensive.
The other thing swimmers do is rely heavily on there strength in the water. They train a lot in the pool, which they obviously don't need to do, do a little running, and even less biking because they lack the endurance land cardio offers (again, because they are always in the pool). As you have found swimming and biking are just two different bears. Swimmers turned triathletes think the swim is going to put them out there at the front enough to keep them out there so they don't train the other legs as hard. If the order was something like bike first, run second and swim last maybe their priorities would be different. The second tri I did last year was an OLY. I was 2nd in my age group to get out of the water. I was passing the slow guy swimmers on the bike (the heats alternated guy/gal by 5 minutes) and felt pretty virtuous until some VERY fast female bikers started wizzing right by me. Gals I probably long had passed up on the swim, but whose forte was biking or running. It took no time at all for them to get enough speed to pass me up. While I held my own in that race, those were ultimately the girls who placed ahead of me.
One more thing to note. Bikers have an advantage in two ways. One being the bike is the longest segment of a triathlon. If you suck on the swim, you CAN make it up on the bike because you have time and then you CAN stay ahead on the run if you have a big enough lead on your bike, even if you're a sucky runner. Two being that biking actually HELPS your running, but running will not help your biking. I have gone an entire season of NO running due to injury and biked in its place. I came back FASTER than when I left with no extra conditioning required. I picked up running where I left off after MONTHS of being out! SO with that said, if you are a good runner, it doesn't mean you will be a good biker BUT if you're a good biker you have more than a fighting chance at the run and thats 2/3 of your entire race right there!
Anyway, that was a good observation you made and there is a lot of reason for it, its not just coincidence. YOU will have a great advantage going into that triathlon. It is important you can more than get by on the swim. Mostly you only need to be at a place that the swim doesn't tire you for the rest of your race. But as far as the rest, if you can get the swim down, it'll be cake.
I had no idea of my pace until my final time. Felt awesome and could have kept going.