The only girls that let that shit go to their heads are ones who don't have a sense of self. Usually already not that attractive and are looking for validation. Most women have level heads and a solid self esteem.
I think so. Also a factor is that hot guys are often willing to lower their standards and sleep with average looking girls as long as they get sex quickly with no strings attached. This leads the girl to think "oh this hot guy is agreeing to have sex with me that must mean I'm really hot too".
The only 'average' guys who have difficulty finding a girl are the ones who love to associate themselves as 'nice guys'. Basically guys who think they're the next Clark Kent because they posses basic human decency and love to bitch about it online.
So no, I haven't really encountered any sort of change as of late, in terms of how hot girls think they are in respect to reality.
no because those guys are desperate for a reason, and the girls can tell. Usually the reaction we have is "wow this guy is desperate" as opposed to "wow I must be so hot." Girls know. Especially if we're getting all that attention online but not in person.