1) The Soviet nomenklatura hadn't recently purged the living crap out of itself to survive internal revolution by workers and peasants, the Chinese had.
2) The Soviet nomenklatura didn't view the establishment of any economy to be a matter of individual or class survival, the Chinese did.
3) The Soviet nomenklatura's economic network was deeply rooted in the firm structure: eliminating nomenklatura control of the firm meant eliminating existing nomenklatura. The Chinese suffered a similar crisis in the "old firms," this was in part preempted by attempted revolutionary activity by old firm workers in 1989 which failed. However, most Chinese industry was "new," meaning that new class relations could be developed. The Chinese nomenklatura could cream newly created capitalist industries.
4) The Soviet economy lacked the capacity for new proletarianisation, this meant that any transformation in firms or replacement with new firms would involve massive structural dislocation in the Soviet working class, which would be politically fraught (1956, 1968) potentially threatening great nomenklatura control of the commanding heights of the economy. The Chinese nomenklatura's control of the commanding heights was not threatened, and a new proletariat was brought into being: this was massive structural dislocation, but not amongst collectively organised urban workers. And the recent cycles of blood letting in the 1960s and 1970s disciplined potential revolutionary activity by workers until, 1989.
5) For the Soviet nomenklatura rather than facing potential revolution, and purging a large body of its corpus, in order to capitalise small portions of the economy that it would not control; it was simpler to face potential revolution, not purge its corpus, and capitalise the entire economy under its control as new capitalists. The Chinese did not have an economy to sell to itself: it had to create one it would own.
Now this doesn't mean that by choosing the other option they'd be out of power as a class, but the die hard fish canning plant factory nomenklatura will have to be sent to camps, and there's a risk of working class uprising.
yours,
Sam R.