I was in a friend's new-ish BMW recently and I felt the interior had a poorly-built, cheap, plasticky feel compared to Tesla. So let's just say that your opinion is not universal :)
I've been in poorly-made non-Teslas before as well. But it happens rarely, since most consumers wouldn't accept cars with the fit and finish issues that Tesla owners ignore for the first few months of ownership. After a few months, even the most die-hard Tesla owners I know constantly complain about all the "small" issues that everyone else would have rejected a car for at the lot.
I've only been in a properly made Tesla once. And they don't make Teslas that way any more (entirely by hand).
Some BMWs do look and feel like KIAs on the inside, especially their lower-end "beginner" luxury models. (That's not a knock on KIA, they deliberately target the low-end market but make up for it with relatively durable cars.)
Tesla have the highest consumer satisfaction so you are exaggerating how much people complain. General its good practice not to accept it until it is perfect, that is true.
And in initial quality surveys while Tesla is bad, other luxury cars are not that great.
Different surveying companies have different results for their surveys, especially as they measure different things.
JD Power, for example, reports that Tesla owners report the highest number of problems and complaints with their vehicles, which is supported by Consumer Reports' owner satisfaction surveys (but CR finds that Tesla owners "forgive" Tesla for these issues and have high satisfaction ratings despite the numerous problems with their vehicles).
CA investigations have found that Tesla has the highest number of cars of any brand that would be subject to lemon laws (meaning defects serious enough to require the dealership to take the car back).
