Great drive UX as opposed to what? Have you driven a modern Mercedes of the higher price tiers? They're pretty damn great to drive or be driven in (comfort and fun wise), but they don't have gimmicks like the door thing and such. If you're talking about those gimmicks I disagree, and if you're talking about "motor/battery/esc technology" I also disagree, they didn't innovate anywhere, they just hit the right market with their product in my amateur opinion.
If they "hit the right market" it means that market had not been hit before, so by definition they've done something new.
I don't have an interest in Tesla nor do I particularly like Musk, but objectively speaking, they must have done something right - they started a mass-car company from scratch in the third millennium, something very very hard; they popularized a technology that had failed to get traction for decades, and have taken the fight to behemoth corporations that had been bearish on the sector's overall future since the '90s. That simply cannot be just marketing or "gimmicks".
