If that (charity) were all you did with completing the design and programming for Pebble Beach, then it would not make business sense. But surely you aren't that stupid.
Reserving Premium courses for premium events to keep them exciting in the initial phase or adding greens fees for an introductory period on a course like Pebble or Pinehurst #2, etc would certainly turn a profit for you with this many players online. Once you'd made the development cost investment back, plus a decent return, you could waive the greens fee.
Since we are buying credits for phantom clubs, balls, avatars, and competitive matches, and since you have a number of advertisements on site, surely you have enough of a revenue stream to support additional course development. After all, you have several courses already. Why not add more?