Asians higher income is, at least a large part, contributed by academic achievements. My family came here with nothing but the shirts on our backs, but like so many asian american now my parents are millionaires. How? They studied hard, which got them good jobs; then they worked hard, lived frugally, saved and invested alot. Which is exactly what "Rich dad, Poor dad" advocated (I've read some of that book long ago). Being good grades often require some of the same qualities being good at your job and successful. My grade is a reflection that I'm disciplined and motivated, willing to go lengths that others would not to secure my objectives, the same ones my parents used to earn their wealth.
But I'll agree with you that some people get good grades using attributes that aren't useful at work. And some slackers might actually be great workers, but both are not general/typical indicators. GPA isn't a 100% accurate predictor of success, but having it as a part of the analysis make it more preditive than without it.
P.S I do intend to do residency because I believe that retail pharmacy will be a dying breed in the long run. All those Pharm.D from no-name schools will swamp the retail market, and reputation/grades will then matter. GPA is already useful for residency as you know, and with increased competition, the GPA and other requirements will only go up. And I intend to augment my degree with an MBA to further my advancement, and GPA will matter for that application.
I stand on my opinion as well. But we can agree to disagree. We each can steer our lives in our own ways.