I guess it depends upon your circumstances, mstewart. Getting unstuck after getting stuck is going to take time, help and another vehicle/tractor. If you've got the time for this, someone to help and another tractor handy then 2WD may be viable. After a few episodes, getting stuck won't be an issue anyway because you'll have learned what you can get away with and what you can't.
But what WILL continue to be an issue is the "work-arounds" you adopt to avoid getting stuck. Taking the long way to a remote field, avoiding a slippery slope, circumventing a soft spot, putting lots of weight on the rears. These all take their toll in terms of time, fuel and/or lost opportunity. If you can afford to do these things over the long term, 2WD should be fine.
But most don't have that luxury. Time is short and, even if we're retired gentlemen farmers, we can find ourselves under the gun due to approaching bad weather, gathering darkness, or the need to be somewhere else. MFWD is on your side when you just need to "Git 'er done".
It's true, 2WD was adequate for farming for decades. It was all the farmers had. But for the acreage, there was more help on farms then and more tractors; help wasn't far away. Now, with huge acreages worked by relatively few people, MFWD can often be a necessity. Help may be a mile or more away.
When new equipment appears on neighboring farms these days, it's seldom 2WD. These are folks that know both 2WD and 4WD, the value of a $, and what's needed to stay productive. When we work by ourselves on our own plot of land it really isn't that much different.
FWIW
Bob