I got certified many years ago as a personal trainer by the American College of Sports Medicine.
I surely have forgotten a lot, and things change, but I still remember this comparison:
Someone comes in to a gym wanting to add muscle, and wants to know how much extra protein they'll need and how to best get it.
Realistically, without drugs, one may be able to add 10 lbs. of muscle mass in the course of a year with dedicated training.
Now, imagine doubling your muscle mass and how much protein that would take. Is that even possible?
Well, what happens to a newborn? Going from 8 or 9 lbs. up to 20 lbs has nearly everything more than doubling, including muscle mass.
And how much protein does this take? Or better, what proportion of the newborn's diet should be protein to achieve this unprecedented doubling of muscle mass?
As an assignment, Google "mother's milk composition" and check the Wikipedia entry.
Point is, it does not require large amounts of protein to build muscle. One should aim to get enough, of course, but if excessive amounts are taken, the excess (which will be most) is simple processed by the kidneys and excreted. At the least, wasting money. At the worst, stressing the kidneys.