A relay attack is probably not that difficult... a pair of flipper zeroes for $170 each is probably enough to carry this out. If someone is determined enough to do this, they'll probably just follow you for a bit and watch you type your PIN to drive as well (with, for example, binoculars). I'd say it takes two people to pull off... one at the car and the other close enough to the driver. Trying to plan the second device on the driver is how you get caught.
Pickpocketing someone's key is another option for people into stealing cars. So is the "Kia Challenge", which I believe is pretty easy to pull off and definitely less expensive than two flipper zeroes. Of course, neither of those methods gets you a Tesla.
I use PIN to drive, and I also lock my bike up. People with bolt cutters can still steal the bike, and two people with two flipper zeroes, a pair of binoculars, and a plan could steal the Model 3. Such is life.