In August 1917 General Lavr Kornilov marched his army on Petrograd (St Petersburg), the capital of Russia.
This was not something that suddenly happened overnight. Kornilov, a Cossack, was a brilliant linguist who in his youth had done extensive exploration of the Caucasus and his native Siberia, learnt numerous local languages, and as an army officer commanded troops from that part of the Russian Empire. They were called the "Savage Division" by the effete St Petersburg Tsarist Court favourites who ran the military, but of course they loved Kornilov, who spoke their languages and lived like them.
Then came WWI, and Kornilov - like his sometime commander Brusilov - was one of the few competent, indeed brilliant, generals of the Russian army. He used proactive and aggressive tactics with a lot of initiative, at one point even breaking into the Hungarian heartland. But like Brusilov, Kornilov repeatedly faced the problem of corrupt and useless court favourite generals like Sukhomlinov and Rennenkampf, who did nothing to support their offensives, and a lot of whom were more concerned with enriching themselves than fighting the war*, and repeatedly had to withdraw from war winning positions as a result.
[*Alan Clark in Suicide Of The Empires, his book on the Eastern Front in WWI, quotes a French manufacturer who bid for a contract with the Tsarist regime to supply tents for the army. The Tsarist official deputed to negotiate terms demanded a gigantic bribe to approve the bid. The manufacturer protested that if he paid that much, he would be left with no profit at all on the deal. "Ah," said the official, (with, Clark says, a silky smile) "I understand. But why supply the tents at all?"]
Then came the February Revolution in Russia, the Tsarist regime fell, and the expectation was that the new Provisional Government would extricate Russia from the by now extremely unpopular war. Instead, Kerensky, the Minister of War, launched an offensive in July called the Kerensky Offensive in the expectation that a victory of sorts would unite the people behind the war. The offensive was a disaster, and instead led to days of rioting in Petrograd. Kerensky became prime minister and responded by making Kornilov the commander of the army. He then possibly ordered him to march on Petrograd to restore order. [Many historians think that Kerensky deliberately deceived Kornilov in order to get an excuse to intimidate his socialist political opponents including the Bolsheviks of the Petrograd Soviet.] Instead, Kornilov interpreted it as his duty to either make himself military dictator of Russia or else the power broker who would impose authority at the point of a gun over the chaos of the Provisional Government and the breakdown at the front.
Kerensky suddenly was faced with a monster of his own making. He dismissed Kornilov by telegram, but that had zero effect, since Kornilov simply assumed Kerensky was now a prisoner of the Bolsheviks, Mensheviks, and other factions in the capital. Meanwhile the Bolsheviks used their contacts in the Russian railway network to sabotage the progress of the Kornilov forces, and their own men in those forces to persuade the soldiers to drop out. Kornilov's army broke up before reaching Petrograd, quite bloodlessly, and the coup came to an end. However, it dramatically weakened Kerensky and strengthened the Bolsheviks, directly aiding in the November Revolution.
[What happened to Kornilov? He was arrested by the Kerensky regime, but "escaped" - basically his own guards let him out and joined up with him - and went on to fight in the Civil War on the White side. He was killed by Red artillery in 1918.]
Now look at the current situation with regard to Wagner. Even Putin has admitted that the Russian military was full of incompetent "parquet generals", and it's not exactly a secret that said generals did not perform professionally in combat.
In April 2022 and then again in September, territory won by hard fighting and bloodshed was abandoned without a shot because the generals did not take the proper steps to reinforce them in time. Prigozhin, meanwhile, is a man who shares the privations of his troops, has in many cases given them a way out of prison, visits them on the frontline, travels with them in the hold of a cargo plane eating what they eat, and not surprisingly they love him and feel a sense of loyalty to him.
This same Prigozhin feels - rightly or wrongly - that Gerasimov and Shoigu are corrupt and incompetent, and either thinks or claims to think that it is his duty to rescue Russia from them and the rest of the "parquet generals". He hasn't said a word against Putin to this moment, but exactly like Kornilov has refused to lay down his arms even after orders from the top authority (Putin in this case). His forces are moving on Moscow, just as Kornilov moved on Petrograd. And it is all but certain that his march will not succeed like Kornilov's didn't.
But just as Kerensky's own actions precipitated the Kornilov Coup, Putin's failure to act in time, either against Prigozhin or against the "parquet generals", created the current situation. This is in the DNA of the Putinist system: it is never proactive, it always puts off even reacting to any situation until no further postponement is possible, and then it does all it can to just restore the status quo. Not even the status quo ante, just the status quo.
In any case, this proves that the armchair generals who have been insisting for the last 9 years that Russia couldn't have destroyed the nazis in 2014 because it needed time to prepare for war were talking through their hats...while calling those of us who repeatedly said Russia should have invaded in 2014 trolls, idiots, etc.
We were right, they were wrong. If Russia had prepared for 8 years there would have been no need for Wagner to be fighting in this conflict at all.