I literally just raised the example of the Chinese communist movement, where nearly 95% of the cadres were murdered by the KMT or perished during the Long March, which involved trekking thousands of miles of arduous mountainous terrains while escaping from the nationalist persecution.

Sorry but that is a bullshit comparison. Your comparison only makes sense if you ignore everything about the material conditions and only focus on "KMT was strong once too".

The Chinese communist party had a countryside to retreat to where the KMT couldn't reach. No such place exists in the US and the countryside is the most hostile to communists. And even then it wasn't until after a failed Japanese invasion that the PLA took power.

Now I don't believe you're actually suggesting US communists take to the countryside. But you're not actually specifying any alternative strategies.

FWIW what's unique about the US isn't so much it the strength of its state violence but:

Already privatized farmland where the closest thing to landless peasants are migrant workers.
Home ownership is still a viable dream for many. iirc there's some Engle's quote where he claims this explicitly.