"Internet of Things" would be better termed "Internet of Security Holes".
A dishwasher with a vulnerable web server; a Toaster susceptible to a DNS attack; a Coffee Maker that has a Heap manager vulnerable to remote execution. This is the sort of thing that "Internet of Things" gives us. It is throwing caution to the wind and attaching all sorts of devices to the Internet because it's the whizbang way, Not for any real convenience afforded by doing so.
There are Coffee Makers that you use via Wifi. You can only really control them via the App. The app is skeumorphic without a hint of irony. It's basically just moved the coffee maker controls from the coffee maker to an App. It's completely pointless especially because you have to be at the coffee maker to put ground coffee and water into it so it can brew, so you are basically using the Coffee Maker exactly like a normal one- but with this App you use on your phone for some reason.
And that doesn't even address that having these devices connected to the internet, in addition to making them a possible vulnerability both in terms of security as well as privacy, you've got a load of more points of failure.
Take a Toaster. It's a simple device. it has heating elements which heat bread. Easy enough.
You look on Amazon and there are $200 Toasters with motorized crumb trays and descent mechanisms. How is that better than having them attached to a lever? Congratulations you've added a Motor that sits in a super hot environment. Gee I wonder how long that will last.
meanwhile there are 100 year old toasters which literally go from bread to charcoal in 20 seconds.
Taking your example scenario, what is more likely to occur is:
You try to get out of your car, but you can't, because the doors haven't unlocked. You haven't driven perfectly onto the parking pad that the Magical Door Unlocker needs to see under the car *Warning: Don't drive into ravines or other dangerous situations, Magical Door Unlocker (tm) will not be held responsible for your inevitable death in these scenarios.* . So you reverse out of your driveway and park again, the door unlocks. So you are now able to open the door. Great. You walk to your front gate- walking right into it, because it had to wake from sleep mode, connect to the internet and validate your regional settings before checking the approaching RFID identity. After a few moment, it authenticates you and pops open. So you walk up to the door. Since the gate detected your presence the door opens, but because of a firmware bug in an update pushed that afternoon it does so at 90 times the power intended, blasting the door off the hinges and shattering the plate glass. The shock wave knocks off your remote doorbell, which falls on the ground, pressing it. This starts playing an unintended song because last night the servers were hacked and all doorbell tunes on the cloud server were replaced with it. You find your dog convulsing on the floor, because when it was scratching itself, it dislodged it's Arfinder (tm) rfid chip, which fell in it's water dish. It's whining because when the rfid was destroyed the Arfinder assumed the dog had left the designated area and started sending it mild shocks, getting more intense over time in order to convince the dog to return to the designated area, Leaving your dog convulsing on the floor, because a recent firmware bug had accidentally removed the upper limit as an attempt to fix an issue with St. Bernards not being coaxed easily. So there you are, trying to wrestle off the dog's shock collar, while standing in a puddle of the dog's urine and being splashed by his convulsing limbs, all while being forced to listen to The fresh prince theme song. Suddenly, EMTs appear at your door, because your car called 911 when you didn't answer it's 40 frantic texts about your Umbrella and assumed the worst.
Yep you're living in the future alright.