I do have some sympathy, as in pretty much any other industry, you could expect a reply to each application. Sadly not in aviation!
This industry is full of wannabes who are so desperate to get a seat in the front of an aircraft, that all normal employment 'rules' are off. They pay for a type rating; worse, they pay to actually work. They apply for jobs that they are not qualified for, or don't have the experience for etc etc. Would you reply to 1000 applications, even when 980 of them blatantly don't meet the stated minimum requirements? Probably not.
Don't get me wrong, we've probably all applied for jobs where we didn't meet the stated minimum requirement - I certainly have, but I wasn't too surprised or upset when I didn't receive a reply.
I'm sorry to say, this industry is f****d up and normal economics don't apply. If I wasn't in it already, I certainly wouldn't join it now.