Assuming its my company and we're a small outfit I'd love to have them but I wouldn't pay 3x (or even 2x) overhead.
1) At a 3x salary you'll need to lose two other employees and sacrifice the redundancy, idea mix etc that you point out. Reducing the HR etc overhead by two employees is far less of a gain.
2) Their higher output is going to be at least partially due to more intensive work habits which may not be sustainable over the long run.
3) If they ever decide to move on you need to hire three replacements and hope they work out and can take over from your superstar without losing too much momentum (all without ever meeting the guy since its unlikely you'll find & hire them within his two week notice period).
I don't know if (2) is necessarily true. Experience, skills, talent, and ability to focus well could easily make this sustainable.
In my experience, (3) happens when they were hired at 1x salary, proved themselves to be 3x as productive, but continue to get just 3% cost-of-living raises. If you compensate them well (and the work-environment remains hospitable), they have very few compensation-related reasons to move. Nevertheless, I agree that they can still leave due to personal reasons.
1) At a 3x salary you'll need to lose two other employees and sacrifice the redundancy, idea mix etc that you point out. Reducing the HR etc overhead by two employees is far less of a gain.
2) Their higher output is going to be at least partially due to more intensive work habits which may not be sustainable over the long run.
3) If they ever decide to move on you need to hire three replacements and hope they work out and can take over from your superstar without losing too much momentum (all without ever meeting the guy since its unlikely you'll find & hire them within his two week notice period).