Why is my tolerance still so low

I’m a 6 foot, 190 pound male in my early 20s. For the last year I’ve been drinking around 40 drinks a week (more heavily on the weekend than weekdays), but usually by the 4th drink I’m still pretty drunk and have to pace myself if I’m out. How come my tolerance isnt higher after this high volume drinking pattern?

On a weeknight I’ll only have 3-4 drinks and still get to a very feel-good drunk, so I just stop drinking