I know somebody has to buy new cars or there would otherwise be no used ones for the rest of us!

Not actually true, at least for those brands with factories in the UK. Most UK manufacturers operate "loan" schemes for their employees and pensioners where they "lend" the car(s) for a few months and then have them back to go on sale at dealers as nearly new, heavily discounted from new price.

The employees/pensioners do pay a "hire" charge to comply with HMRC regulations but that really just pays for the tax, insurance and delivery/collection costs. Manufacturers can afford to do this because, of course, the marginal cost of building a single car is much less than list price.

These are often called "management" cars but the scheme is available to almost every employee/pensioner and managers usually get 2 cars! It's not unusual to have 3 cars a year!

I thought , Hey! I'm a pensioner - then I realised it was only pensioners of the manufacturers (and I think some banks too). You can't win them all!

Don't lose any sleep over it - for the last 34 years I've had in-law connections allowing me to buy cars "on the scheme" - Rover, BMW, Land-Rover, Ford and Ford PAG (Volvo, Jaguar) and I've never bought one yet - usually because private buyers could negotiate better deals but currently because Ford don't make anything I need and Land-Rover are over-priced, IMO.