This is a function of where we are in the 4Runner lifecycle. Their remote start was designed in the age of keys only and that's what you get.
My wife just bought a Bronco. It (like a Tesla) comes with an app which allows you to do all sorts of things, including start the car from anywhere (and no shut down when you get in).
To change the subject slightly, I think Toyota is showing they are late to realize how important software has become to cars. Tesla is miles in front but even our friends at Ford are miles from where Toyota is ...