The problem I have with the OP is that it generalizes way too much. I've seen the behavior described, but I certainly wouldn't call it typical of cam girls. Almost all of the models I've seen who are anywhere close to successful show a reasonable amount (occasionally maybe an excessive amount) of appreciation for tips. I've almost never seen a tip go unthanked unless it was lost in a lot of scroll or happened while the model was near the height of being "busy." In both those cases, it's understandable, and I wouldn't be angry if that happened to my tip. On the handful of occasions, where I've encountered a model with an attitude I didn't like, I just got out of there and didn't come back. Okay, I might have come back once or twice to see if a particular one was always that horrible but generally not. There are more nice ones that I'd like to visit than I can manage already, so an unpleasant one doesn't get to take up my time.
On feeling entitled to tips: well, it depends what you mean by entitled. Assuming they are being entertaining in some way, they *should* get tips from the people being entertained. Projecting the attitude that they feel entitled to it isn't so great though, even though I can understand why they feel that way. Obviously, they need to put in some effort, but I would say almost all of them are doing so. It's a fine line to walk. On the one hand, tips are necessary. The models are there to make a living. On the other hand, talking about tips too much can rub members the wrong way. I don't care if it rubs members who don't tip the wrong way, but I tip without being prodded, and for me, the prodding interferes with the "just hanging out" atmosphere that I like. Still, if it's painfully slow, the model has to do something about it. There's no perfect way to handle it.
I did see one very highly ranked model that puzzled me. I watched her a few times to try to figure it out: she literally spent most of her time doing nothing but sit in her chair and take an occasional puff of her cigarette. She didn't chat at all or even type anything for most of that time. I still don't get it. She was attractive, but there are lots of models that attractive who also bust their asses to be entertaining. Dunno. Anyhow, that's the exception to the rule. It almost never works that way from what I've seen.
As to thinking they're really hot, well, I think the viewers should want them to feel that way, not in a stuck-up way but a comfortable in her skin way. A model who feels sexy will generally come across as more sexy than one who is dwelling on concerns that this or that attribute looks bad. Plus, assuming most members are there to see the hot ladies, why would they hang around with ones they find unattractive? There are certainly (at least IMO) plenty of very good-looking ones to choose from if a particular one doesn't do it for you.
With compliments, I think it's a mixed bag. I'm the way LilyMarie described: I won't give a compliment I don't believe; if I feel like I really need to find something nice to say at a given time, I'll find something I do like to compliment the person on. On the other hand, I do think there are some members who give compliments they might not totally mean just to get attention or maybe, although I think it shows when you're not sincere, just to be nice. That's not the worst thing in the world, but sometimes they go a little overboard. I'm pretty sure some people have told dozens of models that they have "the best <fill in the blank> on MFC."
I do agree with Joe that most men are trained to never say a woman looks bad when asked (I'm not talking about trolls here, I mean a regular guy being asked by a woman he likes). I won't lie about it, but I'll do everything I can to avoid answering the question if my opinion is not so positive. We're not trying to be deceitful with this; it just often ends badly if you're frank about it. The lady often takes it to heart even if she was asking seriously and not looking for a compliment. Sometimes the guy will end up in the role of the bad guy even though he didn't want to say it in the first place. This won't always happen, but it comes up so often that it's pretty much a cliche. So, you get Q: "Honey, do these jeans make my thighs look fat?" A: "Do you want to see that movie about the family that raises ducks?"
tl;dr: Squirrel used a lot of words.