Pay attention to the context. Did Jesus call this rich young ruler or did the rich young ruler seek Jesus out and want to follow Him on his terms?
We only know that this young man sought to follow Jesus on his own terms because of the fact that he chose not to follow Jesus on Jesus' terms.
All of the Apostles were not sought out by Jesus ... at least a few were brought by Andrew to meet Jesus.
And there is no getting around the fact that, no matter what the circumstances of their meeting, Jesus did invite the young man to follow Him.
According to Scripture, the rich young ruler came running and fell at Jesus feet, no ?
Similar to the coming of Nicodemus, no ...
Did any who followed Jesus for a time stop following Him at some point ?John 6:66 From that time many of his disciples went back, and walked no more with him.Yes, but this returns to my previous comment above. Did Jesus call them or did they come to Him on their terms and leave when they could not abide according to His terms?
Of course Judas was one that Jesus called who subsequently left.