"cruisemates" wrote in
oups.com:

My U-67 purchased in 1981 at $1500, today worth ~ $4000+

net cost: a NEGATIVE $2500 - arguably the cheapest microphone one can
buy.

I don't understand why every studio doesn't have a great vintage mic
considering it is one of the FEW fine audio pieces you can buy, use it
maximum benefit, and actually make money on at the same time.

$1,500 in inflation-adjusted dollars is about $3,375 (+125%)
That means your 25 year investment in that microphone has earned a whopping
0.7% (less than 1%) interest compounded annually after inflation.

It's still a great investment in terms of value and use.