I think you are failing to take into account compounded interest and opportunity cost. Efforts you make when you’re young get compounded during the rest of your life time and the time you spend learning the intricacies of human mating is time that you could spend doing so many other things. Especially today when you can’t just start working at a factory at 18 and expect lifetime employment. Not just that, human mating has also gotten a lot more complicated with the advent of the Pill. You probably won’t be marrying your highschool sweetheart either. With the right incentives and a wealth of information I am not surprised to see the population follow a less greedy strategy when it comes to dating and drugs.

Do you think these thoughts are going through the minds of most 17 year olds?

Humans do post-hoc rationalisation for whatever acts they perform and emotional states they experience; I expect Kids These Days have biases in those directions that they may ultimately justify in ways like that, even if the real reason is, say, a general expectation in the last year of highschol that you have three to four more years to go before being an adult instead of just zero to one.