Increased tolerance to THC actually makes it get you less high (for lack of a better term). You need a higher dose to be the same level of impaired. Real stoners can be totally functional and barely even high while hitting a vape every few minutes, but a first-time cannabis user might be on the floor after a single hit.

AFAIK the same isn’t true of alcohol - people who drink a lot may learn to be more functional while drunk, but I don’t believe that someone with a high tolerance has any faster of a reaction time than someone with a low tolerance, if their BACs are the same.