Is this the case?
I rather doubt the most expensive audio products on the market today will be considered classics in the future. Can you even remember the excessively expensive audio products from 25 years or so ago when the excessively expensive but functionally modest if not outright silly home audio thing started in earnest. I think what is missing is that a large proportion of home audio enthusiasts simply do not lust after these products but consider them a bit naff and give them little attention.
If you go back to the 60s and 70s the most expensive products tended to be the top of an identifiable range, they had higher performance, some were a bit ruggedised and "professional", others had home orientated bling like meters and fancy cases but they were all considered to be high performance and top of the range. My guess is that the classics of today are more likely to come from the top of the normal range of home audio products (i.e. £20k products) rather than the products built as status symbols for the rich (i.e. £200k products).