For what it's worth, compounded annually for 74 years (1934 to 2008), that comes to an annualized return of about 9% a year. Not bad by any means, and certainly better than broad market indices have done by a couple percentage points, but also not unattainable by any means, and as you freely admit a new Martin is unlikely to accrue value as strongly.
That said, would I rather own and enjoy a Martin for 74 years, or own and, um, "enjoy" an investment returning 9% a year? That strikes me as a no-brainer.