You missed a few very important criteria on which your old Japanese DD TTs would score nil poi, particularly if bought privately: twelve month warranty (at least); guaranteed not been tinkered with and 'modified'; guaranteed to be absolutely pristine and boxed (if it isn't, get the dealer to exchange or refund); isn't 30+ years old with unknown wear and tear; if it dies the day after you buy it you can take it back to the dealers for an instant replacement or refund instead of slapping it on ebay as 'broken spares or repair' and hoping to get a few quid back.
Replace £xxx with any figure you want and often 2nd hand can potentially get you a better TT/CDP/amp/whatever, but there's a lot to be said for the security of buying new
You may think that I missed the criteria of guarantees. I don't think I did.
I mentioned short-term and long term reliability. It's quite possible I could lose my Top Gear Challenge Game if my tt failed to work when we compared it against a new one. But hey, it's only a game.
If the tt that I bought worked fine for the first year and for the next 5 to 10 years then that would make a guarantee superfluous.
I have already bought over half a dozen 30 plus year old hi-fi components that have worked fine since I bought them over a year ago - well over a year in some cases. I have a good track record here. Would you like me to list these items? Would you like to come to my place to look at the engineering quality of these items so that you can assess the likelihood of them still working in the year 2050?
If I bought a tt that failed in my first day of ownership that was described as fully working I would get straight onto the seller / paypal for a full refund. Generally with 2nd hand hi-fi equipment if it works fine when you first get it, it should keep on working.
Wear and tear? Well engineered turntables will last a lifetime. They are not highly stressed items. They are not left outside in the rain and exposed to corrosive materials. They do not have combustive chemical reactions going on inside them.
For £299 it's possible that I could buy more than 1 well engineered Japanese dd turntable. To hedge my bets.
Ideally 50 or more of us would buy a vintage dd Japanese turntable, run them for over a year and then pool our experience to quantify how important guarantees are for these items.