If you can run a Sub 20 5k, it's not hard for you to win a race if you want.
True. I don't purposely look for small races with weak fields, but if it's nearby and a certified course, I'll put it on my schedule. This year I had one overall win and a second-place at age 58-59 (19+ minutes for 5K). A little embarrassing, but kinda fun.
Even in high school and college, a slow runner can enjoy a win now and then. At least back in the '70s, but I imagine that's still true.
In four years of high school competition, I won a couple track races -- one-mile and two-mile in dual meets. Slow times, like 4:50 and 10:50. In college, I had a few dual-meet 10,000m wins (35 minutes or so ... ).