There were in the past 2wd islander Jeeps. Jeeps that were open cockpit, maybe ran some bikini top, but no doors, etc. Colors were bright and white. So getting around in a 2wd 2k# open cab golf cart is what it really was and if you only took sandy trails and can drive in 2wd, what is the extra weight of the axle/case/driveline going to do, so its not necessary. I'm surprised Jeep took this long to get a straight non-drive axle up front. An XJ 2wd axle would work but they never did it.
Today, a little snow, people drive around in the 2wd cars. You may have 4wd, no wait, think you have 4wd, but all that is going on is 2 driveshafts spin, 1 wheel at each axle rotates (unless there are some type of locker/ls), so you only have 2wd and the cars have 1wd.
Now engineering and design has taken the electronics to play in this game and tire slip control is now added. It works off the speed variance between the wheels on the same axle as well as the other. Some computer controls all of it. Or you may have limited slip, but in time, these wear out and no longer work properly.
Back to the snow, if you have your Jeep in 4wd, then you are still just creeping along like all the others in 2wd.
About the only time I shift into 4wd is when I'm trailriding. The street always sees 2wd.
