I'm sorry, but you can't leave aside those issues - I'd wage that performance isn't a factor in 90%+ of purchases either. Only a headbanger would go out and drop €50k cash on a BYD (or soon to be €60k after the mooted 20% tariff increase). I haven't checked, but I'm assuming there has to be some attractive PCP rental deals ongoing to entice people ?
For a start, what non-BYD dealer is going to take it in as a trade at 5yo - you won't get 10k for it I guarantee you - who the hell is going to buy one at 5yo after the manufacturer warranty has expired (granted, the actual battery warranty is probably longer).
Western Europeans are a fickle lot and are willing to pay premiums for premium and/or well established/proven brands and that isn't going to change any time soon.
Why does the Toyota Hilux outsell the far cheaper (and I'm sure just fine) SsangYong Musso probably 100:1 in Europe ?