Acclimation is complex. Granted, it can take weeks living and working at altitude for the body to become fully acclimated to the point that blood tests and other measurable metrics stop changing. However, most people hiking Mt Whitney do not need to acclimate to that extent. They only need to withstand the effects of the altitude enough to be able to get to the top and back without undue complications.
So with that in mind, even a little acclimation can help. I also take Diamox starting the day before I hike, because it can help a little. (Just don't take too much!)
I can compare my experiences in the mountains... Without any acclimation, I can feel lousy, with no appetite after a single day hiking above 10,000 ft (If I descend, I'd be ok). If I remain at or above 10,000, that feeling will stick with me for several days. When I day hiked Mt Whitney, I could not touch food above Trail Camp.
But now, if I acclimate some: climb a major peak the week before, take Diamox, and spend two nights at Horseshoe Meadows, I can climb Mt Whitney, even spend a night on top, and not feel the altitude to a major extent.
The only other thing I cannot alter is the fact that I got worse AMS years ago. Not sure if AMS diminishes with age, or whether my hiking slower has an effect, or both of those. The sure difference, though, is that I never made any attempt to acclimate before hiking.
One last note: about 25% of the population can climb Mt Whitney and not feel the effects, without any acclimation. On the other hand, a small number can be hit like a ton of bricks, even with careful planning and acclimation.
People really won't know how their bodies will react until they actually go and hike. But it sure doesn't hurt to prepare as much as possible, and also to know what the symptoms are, and plan what to do if the effects of the altitude are to severe.
