a. no one is forcing anyone to work at a certain position, everyone is free to find better placement if they feel they deserve it.
b. there is a reason paychecks are called "compensation." if the price is right, it is easy to stay professional putting aside some of the vanity and ego-bruising.
I have 8 subordinates under me, all older than me and much more experienced. Similarly, my line manager/boss is a female who is 1-2 years older than me. No issues at all although this is in Pakistan in government sector.