...for last few months i have completed almost more than 1500 airdrops and i got nothing there.
Since you yourself have already realized this, that currently the execution of airdrops does not bring the desired earnings, you should stop wasting your time on their execution. You need to direct your energy to other ways of earning money, for example, to complete tasks in the test network. Of course, this will also not be a guaranteed income, but if you are lucky, you can get a decent profit