There are many different definitions of "downfall". Nobody's suggesting the US ride in and dethrone the CCP, leaving a power vacuum in its wake. There are several reasons that would (and should) never happen.

All I'm suggesting is that there is rot at the heart of the CCP, which over time could hopefully eat away at their effectiveness, favorability, and eventually their power over Chinese society. Even then I'm not holding my breath, but it's a nice thought.