They survived that way for millenia, long before mohammad, the desert nomads lived on a knife-edge of survival; where once there were the Nabateans with dams and irrigation, there is now nothing but ruin. When Doughty, who wrote 'Travels in Arabia Deserta' which was first published in 1888, finds evidence of agriculture the tribes simply do not understand what it is or where it came from. Allah put it there. They had no concept of any previous culture.
And now people like the historian Hitti, acknowledged and awarded by The American Universitry of Beirut, who taught at Princeton, is the blueprint for all things arab. His book teaches that the arabs invented music, medicine, astronomy, it was they who were the seed from which sprang the works of the great composers and artists, who began the great works of stained glass in the cathedrals, and were the instigators of the methods used to build the great cathedrals themselves...and your academics let him get away with it, that book 'History of the Arabs' was first published in 1937, and us still used as a text book. It needs to be flushed with the koran.
And in that speech at Al Anzar mosque in 2009, where Malcom X converted to sunni islam in 1964, zero might as well have been reading straight from that book by Philip K Hitti.
This C.R.A.P. has been going on all around us for decades. You only find out about it IF YOU READ!
Thirst for truth...