I'm always happy to hear that a company values their employees, and takes a proactive approach to keep them happy. I'm also surprised how little some companies do on that same front, and only scramble to analyze pay, work conditions, etc. after an employee has announced they're leaving. By then it's too late.
One case that sticks out for me was a few years back when a brilliant lead dev I know left the company he was working for. I knew the company's work conditions weren't favorable, he didn't have a job title worthy of what he was doing day to day, and after hearing the salary he was being paid (about half a typical market-rate salary at the time), my only question was why he hadn't left earlier.
So I think a lot of companies encourage their employees to leave without even knowing it. Or even worse, they know they're shortchanging them on some level and gamble on fear or ignorance in hopes that said employees feel they're getting a fair deal. I believe this to be the case with the example I cited above, and am glad the lead dev has since found a company with much better work conditions across the board.