basically rightwing deviations of marxism that rely on economic determinism to drive the change toward socialism

Marxism does involve “economic ‘determinism’ to drive the change towards socialism”:

“the productive forces, practice and the economic base generally play the principal and decisive role; whoever denies this is not a materialist. But it must also be admitted that in certain conditions, such aspects as the relations of production, theory and the superstructure in turn manifest themselves in the principal and decisive role. When it is impossible for the productive forces to develop without a change in the relations of production, then the change in the relations of production plays the principal and decisive role.” — Mao Zedong, On Contradiction

“Socialism is inconceivable without large-scale capitalist engineering based on the latest discoveries of modern science. It is inconceivable without planned state organization which keeps tens of millions of people to the strictest observance of a unified standard in production and distribution. We Marxists have always spoken of this, and it is not worth while wasting two seconds talking to people who do not understand even this (anarchists and a good half of the Left Socialist-Revolutionaries)” — V.I. Lenin, The Tax in Kind

“…in consequence of the growth of productive forces, out of one system of social life another and higher system develops” — V.I. Lenin, The Three Sources and Three Component Parts of Marxism

At the same time the vanguard party (CPC) still rules, there is still worker’s organization, and, most telling, the Mass Line remains. I fail to see where this “right deviation” comes into play.