"Yeah but who the heck buys a piano NEW, unless they just have wads of cash to wipe their rear ends with."
When I say "used" I don't mean "very old". The very second a 'new' piano is purchased it becomes 'used' and its resale price significantly drops. That's the way the market works. So you tell me, is it really worth paying thousands of dollars more for a piano that says 'new' on the price-tag over a piano that was 'new' 1 year ago in the same condition?
I can't tell from this whether you are speaking from experience or from a theoretical point of view. How many high-end pianos have you seen for sale that are nearly new?
In my long shopping experiences for my first pianos, in areas that had several piano dealerships that featured high-end pianos, those pianos that were "new 1 year ago" were not high-end, performance pianos but, rather, pianos that had been bought because someone thought they (or their child) wanted to learn to play and then decided against doing so. In too many cases, they were production-grade pianos and, although "nearly new," were not worth purchasing at their "nearly new" prices.
The higher-end performance pianos I encountered, including those that had been totally rebuilt were considerably older pianos - 15, 20, 30 years old, or older which raised the question of longevity.
I don't think that many people who buy the more expensive instruments plan on re-selling them within a year or two. Only unusual circumstances surround such sales and, in my experience, they were so rare as to be virtually non-existent.
Moreover, as JP has pointed out, most new pianos come with a limited, non-transferable warranty that can be an added incentive to buying new. I know that in two cases where I had issues with pianos I bought new, those issues were covered under warranty. One involved a long-distance trip from a Yamaha specialist, a visit that would have cost me not only the repair but a couple of hundred dollars in travel expense had the visit not been covered by a warranty.
In another warranty issue, a new part was shipped to me from the factory without question.
I don't think that anyone would argue - I certainly wouldn't - that there certainly can be much to consider in favour of buying a used performance-class instrument in excellent condition, on the rare occasion that one can find such an instrument. Similarly, much can be said for buying new : dealer-manufacturer incentives, genuine (not contrived) stock clearances, warranties.