Kronstadt has somewhat diverted attention from the *other* rebellions that were taking place at the same time. There was actual armed rebellion by peasants, notably in Tambov (ultimately quelled by Tukhachevsky with the help of poison gas). For some reason, Tambov didn't become a cause celebre for the anti-Bolshevik left the way Kronstadt did. Presumably because peasants are seen as less "advanced" than sailors, especially the Kronstadt sailors, the "pride of the Revolution." Indeed, Trotsky and others were later to try to assimilate Kronstadt to the peasant "counterrevolution" by (falsely) claiming that the sailors of 1921 were not those of 1917, that proletarians had been replaced by "peasant lads in sailor suits" who were vulnerable to anarchist agitation, etc.--though in fact the Kronstadt rebels of 1921 were essentially the same as those of 1917. (One difference between the 1921 Kronstadters and the peasant rebels: Unlike the peasants who cried "Soviets without Communists!" the Kronstadt sailors were prepared to accept even Bolsheviks provided that the latter would renounce one-party dictatorship in favor of soviet democracy.)
Indeed, the situation in February 1921 looked like that of exactly four years earlier, with strikes in Moscow and Petrograd, and some soldiers refusing to fire on the strikers. Under these circumstances, as Orlando Figes writes, the Bolsheviks "could not wait for it [the Kronstadt uprising] to peter out. Revolts in other cities, such as Kazan and Niznhyi Novgorod, were already being inspired by it. The ice-packed Gulf of Finland, moreover, was about to thaw and this would make the fortress, with the whole of its fleet freed from the ice, virtually impregnable." (*A People's Tragedy*, p. 762) So an interesting POD would be the Gulf of Finland thawing a little early that year...