Like the person has probably gotten lots of options or they could easily attract many people with effort? There are people like that, but not everyone wants a relationship! Some people want to be alone or they may want to focus more on their career, hobbies or business, etc. I'm being serious.
I haven't but most of the people who know me keep asking me the same thing and It makes me feel like something's wrong with me. It's the worst feeling in the world, people telling you that you would be a great girlfriend/boyfriend but no one willing to actually date you or even seem remotely interested in a romantic relationship with you. This probably won't help but I thought an opinion from the other half of the story might be insightful.
Rarely because looks are only a small part of a bigger picture, doesn't matter how drop dead gorgeous or handsome you are if you have a shitty personality, horrible manners etc then you are going to stay single.
Now if I know that isn't the case then yes I'd wonder a little bit.
No, because in most cases when I see someone like that I just assume they're already taken. In some cases I may talk to them and realize they're single. Then I think: "Wow, how the hell are they still single?"