Despite what some of the replies say, it isn't because of their fall, but because we beleived the stories of their rise.

In the 1960s, some American economists were starting to argue & beleive that "communism" was just a better economic model. Then it all came to a crashing halt.

Once you get past the basics of industrialising serfs, ie they started from a sadly much lower starting point than most Western economies of the time, and account for the compound growth the West had gone through in the 18th & 19th centuries, and then are finally able to look past their Potemkin villages of the 20th century, they were left with no way to proceed. No market signals, no major improvements in consumption. Yes, they had a large (miltary focused) industrial sector, and a large primary economy (as they do now), but their bureaucracy, nepotism & corruption were always going to catch up with them.

Without economic growth, as they got through the 'easy' phases of industrialisation, the periphery was always going to be a problem, then the core.

I'm not sure the "fully dependent on China" slight is needed though, as it could apply to a good chunk of the West at this point. Still, as Europe has learnt with reliance on Russia, these things can be at least factored in.