I was the happy the other day to see four single place Yak 50s, burning a total of perhaps 60 gallons per hour, flying together from my base. They are a relatively new phenomenon for formation fun in the US, and rising in value and popularity. Their utility is approximately zero. People buy what they want, and spend their money how they want. An imaginary draconian vision of 'society' and its 'values' is thankfully not a very powerful factor when people have money in their pockets and want to spend it their own way.
The issue with the old twins is simply that they don't motivate individuals now they way they did as shiny new aircraft. Same thing with a 1980 Mercedes or the older luxury car of your choice, the top of the line always depreciates fastest and worst because age disproportionately reduces its status, which was half of why it existed in the first place, and complexity makes it harder for the individual to maintain. Meanwhile the smaller sports cars and the exotics live on forever.
Today's 310 or 340 has a turbine or two, but I think it's basically the same market in terms of the customer and his motivations.