I may be wrong but the only reason for buying a luxury vehicle in these circumstances would be for work, therefore all costs are tax deductable including depreciation which is usually huge on luxury vehicles.
A mate of mine usually buys a new BMW every 2 yrs as a company car, sells it off to his mates cheap "wink wink" then claims a massive loss & pays much less tax on his huge wage.
I think the reason for the luxury tax may be to discourage people from doing this.

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Beaten up old 98 Gen 2 Liberty, 13.0, stock V3 STI running gear.
07 Transit motor home
69 VF & 70 VG Valiants needing full restoration
Yamaha Zooma 50cc rocket hopefully going with the Transit.