9 of the top 10 boys in my high school smoked daily. 3 of the top 10 girls that I knew of. Usually several times a day including right before school and during lunch. But they were very discreet so you'd never know unless they told you. It didn't harm anyone’s life and most went on to Ivy League schools where smoking is even more common.
The kids you saw smoking near school grounds, failing classes, etc were idiots and failures to begin with. If pot wasn't available, they would still cut classes and drink 40 ouncers down the block.
The last four presidents who have put the country on a path to destruction went to Ivy League schools.