As you say, the Gedolim are against this, it doesn’t result in Talmidei Chachomim, all it results in is men who ‘know how to learn’ but have very limited areas of knowledge in Torah that they can apply their skills to which they forget quickly as Chazorah and bekius is completely negated.
Why is this so? I think because it’s harder and more tedious work to learn and review over and over and over again in order to gain real bekius (as was common in Litvish yeshivos pre-war; they reviewed sugyas over 40 times usually). It takes too long and isn’t so quickly appreciated by peers. On the other hand, a sharp head capable of a deep svorah is more readily admired and doesn’t take much effort on the part of gifted learners. Our instant gratification generation prefers this.