That is not a characteristic of ADHD. Th most damaging thing to ADHD is the myth that the medications affect people with ADHD differently. It is the most pseudoscientific piece of information that is commonly repeated.

As for tolerance, it absolutely happens. Most people do not stay on the medications for a long enough time to really feel the tolerance to begin with. Sure, in a clinical trial of four to six weeks, it might not be noticed. I've been on them for well over a decade, and it's a night and day difference.