I get messages from recruiters based on the very last thing I'm doing, even if I just started doing it in the last 6 months. I got the impression recruiters rar

I get messages from recruiters based on the very last thing I'm doing, even if I just started doing it in the last 6 months. I got the impression recruiters rarely read the LinkedIn profiles. I assume that either most of the people decline right off the bat, or they have a very low cost of processing candidates, because that surely doesn't seem to be a very precise way to look for the right people.