Macrojack,
Most of the responses seem to have addressed the theory of diminishing returns, but you asked about point of diminishing returns. Imagine a plot of goodness as a function of cost. Assuming you have a metric for goodness -- the great devil for audiophilia, at some point the resulting curve will reach asymptot, goodness will cease to rise in direct proportion, or even substantially, with cost. That's the point of diminishing returns. For some audiophiles, cost and the concommitant bragging rights are intertwined, so their sense of goodness rises in lock step with cost. For them, a point of diminishing returns will not exist. Same is true with collecting, where the metric is rarity and rarity usually corresponds to cost.
db
Most of the responses seem to have addressed the theory of diminishing returns, but you asked about point of diminishing returns. Imagine a plot of goodness as a function of cost. Assuming you have a metric for goodness -- the great devil for audiophilia, at some point the resulting curve will reach asymptot, goodness will cease to rise in direct proportion, or even substantially, with cost. That's the point of diminishing returns. For some audiophiles, cost and the concommitant bragging rights are intertwined, so their sense of goodness rises in lock step with cost. For them, a point of diminishing returns will not exist. Same is true with collecting, where the metric is rarity and rarity usually corresponds to cost.
db