I have a different thought than much of the speculation I have seen in the comments. Prigozhin may have abandoned his advance on Moscow because he had proved his point. He took over Rostov-on-Don in a matter of hours, encountering no resistance. This was not only the center of Russian military operations against Ukraine, it was a major supply depot and possesses control over nukes. There are indications that people treated the Wagner forces as liberators, even taking selfies with them. The same thing seems to have happened on the column headed north towards Moscow. Its progress was unimpeded, except for a brief air attack. There is indication that a Russian Pilot, who was instructed to bomb the formation, refused to do so. It may well be that the quick unimpeded progress close enough to Moscow proved Prigozhin’s point forcing Putin to realize the popular sentiment around the country was against him. The message seemed to be that Prigozhin is actually the one in control because public sentiment is behind him.

I think it is naïve to assume that he feared for his life or that he struck a personally beneficial deal. How many more billions does he need anyway? I think he is still firmly in control behind the scenes, and that the supposed exile to Belarus is for show, not reflecting what is really happening in Russia. Prigozhin is not a coward. He would not have given up so easily. I think he made a point about how undefended Russian borders were, and what little support the military had by the Russian population. Having proven his point, he didn’t need to do anything further. The Kremlin got the message. What will happen next will be interesting to watch unfold.