1) Younger people are cheaper to hire in the first place

2) They often have fewer commitments, so more time to dedicate to work

3) They have less experience in the workforce, so easier to bamboozle

4) A lot of them have that fresh excitement and desire to join a “mission” and/or replace through work the peer group they miss from college (which combines well with point 3)

Most companies need very few actually smart people, not sure where the misconception comes from. They mostly need grunts to put in the hours and who won’t complain about their lot.