I'd avoid using Kulaks because this term does not apply to the US current material conditions. But I agree with you, Mao's strategy of encircling urban areas from the countryside wouldn't work because nowadays the rural areas aren't as populous anymore. We'd hardly ever have a strong base there, even if we managed to convince a lot of rural workers to join the communist movement. So yeah, I don't think the strategy is applicable for the US or UK.

In Brazil, which is still an agrarian nation (and on most global South nations that depend on agriculture), this strategy could have benefits. But even in Brazil's case, focusing on the urban proletariat is still important.