Much like Works of Art, the 1911's built by Master's who no longer walk the planet like Swenson, or Bilby, since they are limited in numbers at this point.
Beyond that, the ones by guys like Vickers, or Heinie that don't produce thousands of examples come close... Again, Supply & Demand, and the Supply is somewhat limited.
Towards the other end, Original Classic's like the WW1/WW2 guns, or early Commercial's will maintain good value, as they also exist in limited numbers, but these are more affected by individual condition.
Beyond that, the ones by guys like Vickers, or Heinie that don't produce thousands of examples come close... Again, Supply & Demand, and the Supply is somewhat limited.
Towards the other end, Original Classic's like the WW1/WW2 guns, or early Commercial's will maintain good value, as they also exist in limited numbers, but these are more affected by individual condition.