The responsibility of a true Guru is enormous. They simply can’t take the burden of hundreds of disciples. At most a few
Why?
This is what Yogananda said
It is the duty of the guru and the disciple to be loyal to each other, not only in one life, but for many lives if these are necessary to reach God. Those who are one hundred percent loyal to a guru can be sure of ultimate liberation and ascension. One may have many teachers, but only one guru, who remains as one’s guru even in many different lives, until the disciple reaches the final goal of emancipation in God. You must remember this, once that relationship is formed.
Sri Sri Paramahansa Yogananda
Since this goes on for many births, he simply cannot take this responsibility for hundreds let alone a thousand. These giants take a few Births and come repeatedly devoting their lives to helping a few. During those lives they may perform many miracles but do it so secretly no one is aware of them.
The disciple most remain fully committed to his Guru without fail. If they are not, if they move from one Guru to another, the consequences are unfortunate for the disciple.
True disciple who want to never come back to the mortal chain of the body are rare. Everyone wants to enjoy – few want to stay in the self
Bhavin