Lactic acid does not cause muscle damage. Reps are not done as fast as possible. The concentric is done as fast as possible, but the eccentric is going to vary from person to person. TUT is only a factor and not the deciding portion on the efficacy of a set.
If you're trying to work a specific muscle and you're doing a set at a point which you cannot contract said muscle, then you have bad technique. You're equating pure strength to only 1RM, which is a false measurement of strength. You can argue that a 3RM is more indicative of strength as a 1RM is something that requires a perfect storm of technique, peaking, and arousal. 1RM is something that is generally left and decided on the platform and not in the gym.