Changes to circuit board vibration, to pick one of your examples, relies on tight control of manufacturing as a process. Model 3s had such basic issues as leaks in door seals--does it seem like they have tight control of manufacturing?
Manufacturing prowess aside, this forum has a pretty big collective eye roll at management and consultants and business 101 topics generally, but when you talk about things like "getting photos from a failed part direct to an engineer" you need to be asking whether those departments are set up to communicate with one another.
I'd expect them to have sensors on the individual MOSFETs though - there is per-component variation, and software changes can benefit per-component efficiency. I could totally believe a gain of +1% efficiency from such tuning, and probably more like +30% peak performance, since components can be pushed far closer to their limits when you know the exact temperatures.
They can do things like measure vibration of a particular circuit board across the fleet, compare that to the design specs, and be able to predict failure probability a long time ahead of real failures. In turn, they can then revise designs to avoid a failure mode that hasn't even occurred yet. A failure that would have affected millions of cars now only affects thousands.
Lots of things can be mitigated with firmware changes - for example, if you see a specific MOSFET getting hotter than expected during regen braking in cold climates, you can adjust the drive parameters to avoid shootthrough, preventing it failing 10 years down the line.
Couple that with tesla employing service personnel ought to mean they can get photos from a failed part direct to an engineer within a few hours to see if a redesign is warranted. You can't easily get that through third party repair shops.
Overall, Tesla seems to have so many advantages in the reliability/quality department, yet news articles don't seem to match. I wonder why?