Maybe it's the other way round and only new cars do this - I'm in my late 30's, my cars are never younger than 15 years old! I haven't even yet made it to cars with the "new" number plates, I'm still on a T-Reg!
They have all had central locking, driver boot release (a cable that runs back to front on the car, it's hardly high-tech!). and some have had remote-control boot unlock (but - again - the boot is ALWAYS locked otherwise).
Don't want to lock the boot? Don't close it. That's how EVERY car I've ever used has worked, so I find it odd that people want to leave the boot unlocked?