There are over 30 strains of HPV with just 2 causing the majority of cancers. So sure, most people may have had some strain of it, but that's not really relevant unless immunity is broad across strains.

Or, you could have been suddenly cheated on and exposed, or divorced and recently entered the dating market, or thinking about opening up your relationship after decades of monogamy.

But the number of such people is low, it would not be easy to find candidates for the trial. Just because there are some doesn't mean there are enough to make it worthwhile for the drug company to do the testing to be able to market it to such groups.

Maybe, but all 9 cancer causing strains covered by the vaccine? HPV also clears on its own usually after some time afaik.

Sure, but you probably don't already have all the strains which can cause cancer.

Yeah that makes much more sense as an explanation than OP.