Men are not as prone to injuries, especially not bone-related injuries like stress fractures. The male fields are also deeper making it less likely that someone with triathlon-style training would succeed. As far as I know an older very good athlete who became better by incorporating a lot of alternative training, because less injuries, is Eilish McColgan.
But as has been pointed out above, at the highest level and especially in shorter distances than half marathon, efficiency, mental toughness at race tempo and kick are very important and probably the decisive factors not aerobic conditioning that can be done quite well with alternative training. That seems another reason why the faster men can not thrive on a lot of alternative training, because the factors specific to running are more important. Otherwise there would have long since been male world class runners doing huge training loads on bikes or so (up to the amounts of triathletes) and beat the "mere runners". But there aren't.