I'm seeing a lot of people with kneejerk reactions, so I want to highlight a points:
ADHD is very easy to diagnose. Unlike autism, which requires a whole day of screening and thousands of dollars, ADHD can be diagnosed in an hour. However, when this happens, parents are usually very receptive to medication because it's both an easy fix and they're probably struggling at home for any number of reasons. If you're slammed, working two jobs, stressed out, barely able to pay the bills, and a pill that promises to make your kid be able to get through their math homework without crying comes along, you'll take it. The alternatives like therapy and parent coaching and stuff are difficult to get, unfortunately, and while schools are technically supposed to provide support, that's an issue. The other issue is that a lot of kids that may be autistic are getting ADHD labels- you've got a kid that gets distracted in class? It's entirely possible that they are autistic and struggling with sensory overwhelm so it's hard for them to think clearly, but ADHD is a convenient dx. Finally, there's long been a real push for pharmaceuticals to be prescribed at a young age, with drug reps targeting both teachers and pediatricians. While providing meds to help, unfortunately for them to work out in the long term it's critical that kids get therapy to help them manage their ADHD, and more and more, that's just not available, so it just becomes a band aid the kids become dependent on, then as their bodies and brains acclimate to it, they have less and less ability to function, so you end up with serious issues in young adulthood. So, unfortunately, a lot of kids get screwed because they aren't getting the essential therapies they need to be able to balance meds with an ADHD toolkit.