Your Wells Fargo story is very similar to mine when I tried withdrawing 15K at a branch that is not my local branch. The money has been sitting there for years, and I rarely used this account. An hour of back and fourth and they would not give me my money that morning. I had to come back later that afternoon at which point they did give me my money.
Most of these banks have fairly straightforward algos that look for unusual account behavior. If someone is depositing X and withdrawing X all the time, it does not trigger any flags and you would be surprised at the huge transactions people do painlessly all the time. But if a transaction stands out compared to typical account activity, it triggers some warnings in the same way that we sometimes have to enter our zip code at the fuel pump when we go on a road trip to areas we usually do not go to: unusual activity that does not jive with account transaction history.
Are retail banks antiquated? I'm not so sure. They are opening up more and branches here on Manhattan to the point that people are complaining that half the street is more bank branches.
As for dealerships, they have been making tons of money via service departments. Commissions on cars are miniscule compared to the margins at the service dept. Those car sales drive lucrative years of service bills. That's my impression anyway... There is a great This American Life podcast episode about a car dealership selling cars you might be interested in.