We cant know for sure, we can speculate though. :)
It could have been a number of things. My guess is that he either didnt have the balls to actually get rid of Putin and go through everything that would entail or that he just didnt get enough oligarch support he expected to get.
The video where Putin is panicking and calling what he was doing a betrayal might have done its job inside Wagner to soften their resolve.
Again, its hard to tell.
Yeah, the time will tell. Ukrainians are probably celebrating though :)
Thanks for your updates!