Commissions are an integral part of airline sales. Not all sales are 'straightforward' i.e. from Point A to B but many BUSINESS TRAVELERS go from Point A to B to C back to A.
It might be cheaper to PAY motivated 'agents' than employees who are always looking for a higher pay for less work!
Agents book tickets, change dates, advise on travel dates, etc [Basically what they do might have to be done by salaried employees]
Last year, I wanted a last minute ticket [not allowed online] so I went to KQ's offices. I had to wait till they opened [9am] - they refused to 'open' prior to 9am... Would an agent keep you waiting?
Greedy when others are fearful. Very fearful when others are greedy - to paraphrase Warren Buffett