They know they are hot... and because they are nice... They want a responsible, mature women, and they will wait till they find one... They get picky and they can be... Because they know they are a really good catch and want a girl who will see that...
Men and women both tend to gravitate to people of equal attractiveness to them. Women are more likely to place less emphasis on appearance, but that's not a hard rule. Obviously every couple is an individual, but as a general rule attractive people date attractive people because they can get attractive people.
People rarely date outside their "league" - but it needs to be remembered that men and women have different criteria to make their ratings.
But someone who is a 10 (or close to it) is going to have a ton of options, and be in very high demand, and so they're almost always going to take advantage of that and hold out for another 10. They're rarely going to choose a 7 when they've got a thousand 8's and 9's (and a few 10's) anxious to be with them.
So, yeah. Rarely do people date more than one level above or below their level - whatever that is. And in the event that they do, there is usually something else going on. For example, hot young women getting with 80-year-old men doesn't happen - unless the man is at least a multi-millionaire or has massive fame/status.
hot or not, every guy wants a hot/attractive girl. for us (guys) its just based on luck in who we end up with. with girls its more simpler because they get to choose and succeed due to not having that high risk if rejection, and guys fall in love faster and easier than a girl. thats why its best for the girl to approach who she wants when she wants.
I would say most people date within I guess their league, you will see those couples who in a way don't "match" but doesn't make it a bad thing. So to answer your questions no hot guys don't always go out with hot girls. It depends ;)