I donno, I'd agree that pot could be considered a gateway... in high school we would always joke about the "two goods": weed and alcohol. Anything else we were supposedly not going to try.
Things have definitely changed since high school. We're not THAT hardcore, I'm not trying to come off as some badass or anything haha, but between us we've done shrooms, LSD, coke, aderrall, and salvia. None of that would've ever gone down if we hadn't started with those things in high school. Just my opinion.