What portion of Telsa's pace of improvements and innovation would you say is due to Telsa only recently having got started at this, 16 years ago, compared to Toyota 86 year history of automobile manufacturing, or Ford's 116 years.
It's not so great for hardware, because iteration means that newer builds of existing models may not share the same parts or designs, increasing the costs of maintenance. It's even worse for consumer hardware, because consumers will do all sorts of crazy things to/with their hardware.
Tesla couldn't keep up with the demand for repair parts before the Model 3 surge last fall. How will they manage if every part essentially needs to be custom made since they're constantly changing the parts?
That's not what happens in practice. Their revisions still obey interfaces wherever possible and follow the principles of modularity. E.g. when a v1 Model S door handle breaks, they replace it with the v3 version. When a v1 battery fails, they replace it with the v6 version.