Come to think of it, neither did a couple of the cars I used to have. Could be a “feature” on different models/makes. Ours are Fords, and unlock when you touch the door if your fob is in your pocket or close by. No hard key any more, just a “Start” button.
Yes, my key (2008 GM) is just a button activated radio transmitter (315 Mhz) with no proximity sensor on the vehicle side. Once the key is inserted in the ignition, however, the pass-key system does verify the chip code.
I would just as soon get rid of all the electronic stuff and go back to mechanical fuel injection and no ecm, personally.