Some of Tesla's vehicles are priced to compete with Porsche, high end Mercedes, high end BMW's, Land Rover's, etc. The things all those car manufacturers have in common is quality fit-and-finish on their expensive vehicles.
When your brand new vehicle has mis-aligned body panels - it does make you wonder what else is mis-aligned that you can't see...
Body panels being mis-aligned isn't some new manufacturing technique Tesla is experimenting with - that's just plain shoddy workmanship and a total lack of quality control. You cannot just hand-wave those issues away, particularly at the price point Tesla has maneuvered into for even their less expensive offerings.
[1] https://teslaownersonline.com/threads/pre-delivery-panel-gap...
[2] https://teslamotorsclub.com/tmc/threads/body-panel-alignment...
[3] https://teslamotorsclub.com/tmc/threads/panel-mis-alignment-...
If you watch tear down by Sandy you can compare old Model 3 manufacturing and the new Model 3 manufacturing. There is a lot of changes in welding techniques, amount of welds etc. everything gets simplified and more streamlined. With one piece casts as the final goal.
Are we to believe Tesla has zero QC? How do things like this occur? These are all solved problems companies like VW figured out decades and decades ago... Tesla is just insisting on figuring them out on their own all over again.
I highly doubt QC was sending cars out they didn't know about - it simply was too time consuming to manually fix, so they only fixed the absolute worst ones and hoped most customers wouldn't care enough to force them to fix later.
Tesla is some mix between car company and software company. Someone did a calculation where it was cheaper to ship now and take a hit on the % of customers they upset. That someone obviously was completely vindicated in their decision - the vast majority of their current customers apparently do not care enough body gaps to stop buying.
It's not like there are hundreds of books on the Toyota Production System. It's not even a secret. He had to actively ignore it.
https://www.forbes.com/sites/joannmuller/2018/02/16/tesla-th...
Also in the TPS you only automate processes that you know exactly how to do manually. Elon tried to start with automation from the start, ignoring that automation of processes you only know partially ends up multiplying your quality issues.
Besides, the quality issues are mostly cosmetic, structurally the cars are very sound. Look at crash test data if you don't believe me.