I don't think the actual building of a Tesla is subpar. I think it is lacking as it rolls off of the line. My mother in law retired from a Honda manufacture plant a few years ago. Honda (I'm willing to bet most manufactures) have the same issues with miss aligned panels, paint defects etc. She's told me stories of doors that damage the front fender the first time they are opened, random dents in the body panels and other things. The difference is how they handle them. As a Honda rolls off of the line it goes to a section (I think they call it Final) where it gets inspected by several employees. If a gap is out of spec they try to fix it often times this could mean using some persuasion with a hammer. If the paint is messed up they try to fix it. If it's too far messed up the car gets sent back for the messed up sections to be corrected.
Honda employs lots of people for this step and has the luxury of having so many cars being produced that they can send it back for corrections or even scrap a bad one. Tesla cuts costs by not being as strict with their quality control. Basically they get the consumer to do the quality control inspection for them. Instead of spending money finding and fixing issues a consumer might not care about or notice, Tesla fixes what the consumer has an issue with. Their quality control for fit and finish is too lax in my opinion but a company that is spending more money than its bringing in on sales has to make cuts somewhere. Their development is what's keeping them afloat so that's where their focus is.
Honda employs lots of people for this step and has the luxury of having so many cars being produced that they can send it back for corrections or even scrap a bad one. Tesla cuts costs by not being as strict with their quality control. Basically they get the consumer to do the quality control inspection for them. Instead of spending money finding and fixing issues a consumer might not care about or notice, Tesla fixes what the consumer has an issue with. Their quality control for fit and finish is too lax in my opinion but a company that is spending more money than its bringing in on sales has to make cuts somewhere. Their development is what's keeping them afloat so that's where their focus is.