I worked for a company that did this very successfully for a long time - they paid very high salaries and had lots of nice perks so that people weren't tempted

I worked for a company that did this very successfully for a long time - they paid very high salaries and had lots of nice perks so that people weren't tempted to jump ship for financial reasons. However, as tech salaries have increased the last few years, they have hit the problem of people jumping ship after a couple of years, presumably because they can now earn more as developers in the finance sector or with Google, Facebook etc, though I expect something more subtle might also be going on as the company has grown in size.