As you go skidding down a hill in 2wd, how are you going to put it into 4wd while pooping your pants and hoping the things does not go sideways on you?
Shoot! I've totally experienced this with just wet grass on turf tires in my 2wd ford with 60"mmm on my hills You learn to
avoid those situations and get a
bit used to it after it happens a few times. Getting stuck on a slight slope in half-frozen muck is a "joy" I will never repeat on my Kubota.
Back to the original point, I use 4wd all the time and rarely switch to 2 due to my terrain and the work I am doing.