parking garages/lots would be incentivized to work with manufacturers to come up with automated ways to check in and out because it directly leads to more revenue for them (and less hassle with accidents I'd bet)

Just availability is already available and popular in some cities, Seattle for instance http://www.seattle.gov/transportation/epark/default.htm

I think you're vastly overstating the complexity of figuring if a parking spot is available and paying for it.