I might agree with you, except that the Poles were still Catholic at their core (that’s why JPII was able to have so much effect in the 1980s); the USSR collapsed because of the weight of trying to keep up with the US militarily; and in Cairo, the result was not that the government reformed, but that the military staged a coup. A similar, perpetuated mass demonstration in DC and other major cities could also lead to a military coup in the US, but that isn’t something we should hope for, because that would turn us into Chile under Pinochet.