Which to him was self-evidently not true.
Also according to Mandel, it was self-evidently not true that socialist revolutions do not lead to the establishment of a Marxian socialist state, but rather bureaucratic states. This is an old Trotskyist adage: that socialist revolution was subverted and betrayed by Stalin and his cohorts, but otherwise, it was perfectly socialist indeed.
This statement was in direct contradiction to the analysis of James Burnham (Managerial Revolution).
Mandel wrote down his vision back in 1979, when the Soviet Union was seen as somewhat flawed, but still second World Power, which just needs a few more reforms to straighten up, nudge the parasitic class bureaucracy off its position and become the futuristic Marxist republic, based on the production of goods and services free from private ownership and dictate of the bourgeoisie.
According to Mandel, it was the bureaucracy that was in crisis, both in the West (together with capitalism as such), but also in the Communist East.
As of today, it is perfectly clear that James Burnham was perfectly correct, while Ernest Mandel practiced wishful thinking. Alas, particularly instructive history of Perestroika and the collapse of the Soviet Union did not teach Western Trotskyists - turned - neoliberals/neocons any new trick.
Still, it is useful to look backward and summarise.
Bureaucracy, combined managerial elite of corporations and nation-states IS the de-facto ruling class, and the more "Socialist" the State is, due to revolution or course of reforms, the more numerous this class becomes and the more concentrated power it has by necessity. Previously independent institutions, including academy, police, and courts, are becoming subverted and subjugated by the state bureaucracy with its distinct hypocritical ideology of the ruling class.
Yet Mandel is correct about one thing: the self-interests of the Managerial Elite / Nomenclatura class run contrary to the national interests and false of its own proclaimed goals, which is particularly visible if one tries to apply the Marxian historical materialism analysis to the situation.
Socialist Bureaucracy bankrupts the nation with ironclad inevitability.
That is also why it needs the whole world as a place to escape from the sinking nation, this is where it's internationalist and multiculturalist aspirations are stemming from.
Except in the USSR, where Nomenclatura had plenty of internal natural resources to trade, to attach itself to and be content with, and by simply trading these resources to the West, to have the most indulgent, irresponsible, well protected, and prosperous lifestyle at the expense of the core of the nation, which was reduced to largely neglected cattle (bydlo), which is routinely sacrificed in a cargo-cult mimicking the Western Law of the past, classical liberal era.