Bringing in your own trained personnel solves one of my biggest gripes with auto dealerships...most car sales staff have no real knowledge about the product they sell. They rarely do their homework.
You got that right. But the same can be said about Best Buy personnel. They rarely know anything about what they sell either. Price is the excuse people use to not buy there but I suspect it's the experience and the limited selection that they really don't enjoy--there often isn't a large difference in price. The problems large brick and mortar stores have are:
Is the model you see in the store really the latest model?
Is the model you see in the store the best model, the worst model, something in-between?
Has the product been
cheapened for that that store so they can sell for the price listed? This is particularly a problem with branded products.
Is the salesperson telling me the facts?
Now all these questions can be answered with research, but if you're doing that much research you might as well save the trip to the store.
There are some things that are either perishable or need to be fitted, so grocery stores and clothing stores are unlikely to go away. For cars you may need to sit in them, get into and out of them, etc.--particularly if you are extra-something because cars are generally designed to fit 80% to 95% of the population and
fit is somewhat subjective.
My real concern about Tesla and dealerships is the
service advisor model where you don't get to talk to the person who does the work on your car and have to hope that the advisor passes on what you told them. This has caused no end of frustration with the Prius, and is one of the two big reasons I'm going to pay 3X for a Tesla.