There are some survey out there that ask about what percentage of people are into bdsm or have a foot fetish or something like that. I can't remember where I saw them but I don't remember seeing chastity on those sites. You could use that data to compare it to an interest in chastity by comparing them on google trends to get an idea of the percentage of people interested in chastity.
I’d say most males would be willing to try chastity if presented with it. Getting most makes to openly admit it is a different story
I’ll resoectfully disagree with you and agree with MattL. Men are weak and well do just about anything to please a woman. So it’s all in how it’s presented. My own experience is most people are open to some light kink. They’ll laugh about it and such in public but in private discussions be willing to try things such as light bondage, blindfolds, etc. So unless a guy is either insecure with himself, a religious fanatic, a male chauvinist pig or just a jerk, I’m willing to say he’ll try chastity if a woman asks.