My personal experience with this is that patents are only used as a kind of status symbol, in that they help researchers acquire new grants/funding ("look, it's marketable!") and make themselves look good to their institution. I'm yet to meet a researcher who's actually made any money off one, and most are by no means adequately compensated for their work.
That all said, I have met former researchers who've made successful start-ups from their academic work, and made money that way, and I'm sure patents were an essential part of that, but by that point they've left academia anyway. For them, I never had the impression that the prospect of making money was the motivating factor for getting into research. It was all just serendipity. Though I'm sure there are exceptions.
Oh, wait, he didn't.
"There is no patent. Could you patent the sun?" - Salk
Bringing discoveries and inventions into the public domain for the good of society is the primary reason for having a patent system. To the extent that it inhibits this outcome, the system is failing.
You should see what happens when they realize they aren't ever going to become filthy rich someday from their discoveries... just like everybody else.