Prigozhin wasn't a general, he was a businessman. Even if he was Stalin had plenty of generals executed.Personally I find this very unfortunate.
Wagner was Russia's most combat-effective unit, and in Prigozhin Russia had found a very potent military leader. Now Putin destroys both to preserve his power. Imagine if Stalin had murdered Zhukov in the middle of WWII.
How can Russia win when Putin keeps on purging its best generals? We never see lunacy like this on the Ukrainian side.
If what the Russians are claiming is true, and he did attempt a coup (which I still have strong reservations about), what do you expect him to do? Let him go scott free? What message would that send out to other would be coup plotters?
I also don't believe the idea Wagner were Russia's most combat effective unit. Most of their soldiers were drafted from prisons with minimal training. What's so special about Wagner that turns convicts into elite soldiers?