German badges are not +£10k more expensive, that's kind of the point because a Tesla Model 3, Model Y, Model X, Model S cost the same prices as Audi, Mercedes or BMW. You can delude yourself as much as you want, but among the vast majority of people (not just EV owners), Tesla is not even close to being more desirable than the German luxury segment.
I agree that Tesla quality has improved but the fact iyou even mentioned it kinda helps prove my point, because even when it was worse the prices were always at luxury levels.
When I priced leases on the Mach-E AWD ER, Tesla Model 3 LR and the Audi Q4 50 Vorsprung Sportback. The Audi Q4 50 was actually the cheapest. Hell I could get an E-Tron GT for less than a Model 3 LR on a lease through work.