Re: Lease don't buy
Three quarters of new cars in the UK are currently leased rather than purchased outright - I suspect we will see current buyers transition to leasing and current leasers transition to Uber-style hiring (without the driver) in cities large enough to support
I'm less certain how rural areas will cope if they can't justify the economics of the new transport industry - I'm guessing edge of zone car parks and moving into hire/public transport vehicles.
As far as congestion goes, all the traffic simulations I have seen suggest reducing accidents (and associated delays) and impatient driving will lead to significantly more capacity on major roads.