It is now my opinion that craving is the "modern natural default condition". The only variation is what we are craving. We are being trained to want "stuff" and to fulfill those desires. Before WWII the traditional training in to suppress the desires, at least when possible. Reading the Stoics, and various historic family records, a pent up desire of some kind seems to be the driving force behind so many of my ancestors, some achieved and satisfied those desires, some did not.
Often the desire was more education, more knowledge, and as I look back on my life, that to was present and active. The difficulty I had was making a great deal of money off my knowledge. I wanted to do the work, not get a bunch of half-twits and heard cats. Anyone who has run a technical knowledge based business will know exactly what I mean. At a result, I made a living, and did not get rich, but also had time to learn much, and was professionally competent in my little area of expertise. (geotechnical materials; much math, statistics, testing, measurement, analysis of soils, foundations, concrete, asphalt, and related materials, including industrial and human waste, geotextile design and applications, and forensic analysis of any of the above)
Anyway, back to cravings. There are a number broad sources or causes, environmental, physiological, psychological, and philosophical. I use philosophical here at a personal level, almost psychological level, much as the old stoics did. One idea can eliminate a whole bunch of crap. We have been trained by our culture to crave, and satisfy the cravings. Do you remember hearing of the through away society in the late 60's? The stoics acknowledged the cravings, and did what reason told them was right. Getting the knowledge that they were right, and virtue was on there side, gave them the passion to overcome desire. "I did everything right, the fault must lie elsewhere"... type of attitude. It is human nature to crave. Learning to direct the passion, the motivation to action, may be the method of overcoming desires. This is similar to keeping so busy that I do not have time to eat.
But what do I know?