In an office job, the most common way to increase your pay is to show a higher level of performance than your colleagues. A healthy level of competition amongst the workforce is of course benefitial but unfortunately human nature dictates that far too often people resort to back-stabbing, politics and even sabotage against their own ranks in order to achieve that aim.
If it wasn't obvious before, it should be by now: airline pilots are not supposed to try to out-perform their colleagues in pursuit of a bigger pay cheque. How many ways are there of 'doing a better job' than another pilot which doesn't reduce the safety margin of the operation? Imagine that our pay is correlated to how I am able to push back on time whilst carrying a technical defect or how much savings on fuel we can individually make for the company during a typhoon.
The pay increments based on seniority is the company's promise to me that the bottomline is that I only need to be concerned with flying safely. Doing the job more efficiently and with finesse is a matter of my professional pride.