The pictures of the carvings are stunning- if they are as old as they are supposed to be, they are revolutionary.
It also provides a more convenient basis for taxation. :)
Anyone who has ever gone hunting knows that it would be a rigorous lifestyle if you had to live off of your kill.
Huh? Your statement suggests he was just wandering about looking for something to do, and eventually decided on farming. Forgive the slam, but I'm more used to such sideways inaccuracies in the liberal media. David was being hunted by Saul. Until Saul died he was always on the run in spite of his attempts to reconcile the relationship. When Saul was dead David took the throne. I don't think he did much "gardening" then, it was done for him.
"If you ever do extended survival training, you'll find that it takes a lot of work to get food by finding it here and there throughout the year. Plus, it is not assured that you'll find enough in any one place."
If you're ever reduced to really extended survival training, of the sort where nobody is going to come and rescue you, ever, you'll find that it does not take all that much work to get food by finding it here and there for about 9 months of the year. Roll over stones and turn over logs: there are plenty of insects and worms and all sorts of nasty protein sources which can be eaten, and which will keep you alive. Most green stuff can be eaten, but most of it is not really necessary. Bugs and worms will keep you alive, and they are plentiful just about everywhere. And horrible.
During snowy periods...well...there's a reason naked mankind didn't develop in the temperate and subarctic zones!
For that, you have to live off all that stored bug fat, and store up acorns (which are horrible, but edible). The inside of pine bark will keep you from getting scurvy (and is also horrible).
Life as a wild man is short, but it's not really starvation that gets you. There really are enough bugs out there to keep you alive indefinitely. The problem is that the combination of cold and exposure lowers your immunity, and you die of illnesses and infections much more quickly. A cold becomes the flu becomes pneumonia, and pfffft, you're worm meat.
"The story of King David is about switching from a nomadic life to one of agriculture"
The story of King David was one of his being part of a shepherd family, then anointed King because Saul had lost God's favor, but not yet able to take kingship becauese he was being hunted by Saul who wanted to kill him. David killed Goliath which raised his stature with the people, thus raising Saul's jealousy! That was the reason for David's earlier wanderings.