Not really, Most people keep more then one male with their females, so they never really notice.
and those that don't you have to remember females hold sperm from one mating for several months or more,
If like some breeders, keep virgin females then you will find you run across sterile males every now and again.
Even many professional breeders keep more then one male with their females, At least until they know a male has proven himself.
Their is another thing with platies, Some can be so timid & nervous they just never seem to think about mating,
I ran into one of those in my black tuxedo's not to long ago. Was the only tuxedo male I had left as it turned out,
I just realized one day, Why have I not been getting young from you guys anymore, Thats when I saw only one male, oops, sold too many males back when, and the females were not holding, brain started clicking, I can be so dumb some times, The only male in the tank was a chicken chit, always darting and hiding over the least little thing,
So I changed him to a different tank where it was more isolated, on a shelf, back corner with only one end showing, Lots of cover, then left them so see what came of it. alittle over a month later I started getting fry again.