No arguments regarding the price and "expensive" discussion, so I'll consider that this matter is settled and that you agree that the higher price is irrelevant.
Now, before I talk about the use, let me make something extremely clear: I'm saying the AWP is OVERPOWERED. Something can be slightly overpowered, just overpowered, extremely overpowered, or straight-up broken. The Krieg and the AUG were overpowered, but not every rifler was picking it up, the OLD AWP was even more overpowered, and it was nerfed, but not every player was using it, the use rate was probably lower than what it is right now.
Also, when your main argument is about the price, and you can't say anything after I point out use rates, I pretty much already won the debate. A strong, easy weapon that has the downside of "cost" being irrelevant is indeed already overpowered, and the 2019 economy changes only accentuated that.
Now, about the use. Everyone knows that the best awpers nowadays (s1mple, device, and ZywOo) were riflers, and some of them even say that they would rather rifle, and that happens because the weapon is boring as fuck. As s1mple said, he only started awping because it's the easiest weapon in the game. Being a CS:GO pro is already a hard task, you have to grind the game 7 days a week, now imagine doing so when you have to play and abuse something as unsatisfying and easy as the AWP, only a few are able to hand this torture. Second, the awp has one weakness indeed, and that's why HAVU used 4 awps and 1 auto sniper when coming back in that 5 snipers game. When an awper gets rushed and he mollies an entrance, the Ts are able to smoke it and rush through their own smoke, and in this kamikaze move the awper is usually "ONLY" able to get 1~2 kills before falling back, while a rifler would be able to get 3~4 kills. So, adding the complete boredom that is playing with the awp with the fact that a m4 would be able to get more kills when players are kamikazing through a smoke, some players would rather keep their mental health and rifle.
Anything else? Any desperate last arguments?