Great question! At this point I am no where near as educated on the electric vehicle economy as I used to be. From a physics standpoint in-wheel motors are more efficient because energy dissipates when you have to send it from a motor through some mechanical linkage to the wheel. But that doesn't mean it's the ideal solution for every electric vehicle. At the end of the day I look for companies that are going to evaluate the current state of the art and make the right calls with respect to where they allocate resources so that they can execute a product that delights their users and can scale. When I see companies saying stuff like, "Oh we're going to make an awesome car because we have in-wheel motors (or solid state batteries for that matter)," it always sends up a red flag because making an amazing product, but more importantly making an amazing COMPANY, is a lot more than one single component and there is never one single "right" answer. The fact that Tesla is integrating in-wheel motors in specific use cases shows that they probably have a lot of utility, but they're probably still just too expensive for a low-priced mass-market offering like the Model 3 where using components that are already being produced at scale are important. Semis are expensive, so it makes sense that they can experiment with new tech in them, in fact, this might be one of the reasons (just one of many I'm sure) that they were interested in expanding out into that market. At the same time semis are a huge market and after their presentation I have little doubt that it's only a matter of time before Tesla dominates that market. I think that will probably happen even before they dominate the regular car market (mainly because it's so much bigger).