Interesting theory, need to think about that. Though I don't think Fascism and Capitalism are necessarily exclusive. (As example China, which is I'd say fascist and against the usual theory of "communism" quite state-capitalistic)

China is not fascist. Read Ur-Fascism by Umberto Eco. America fits the commonly accepted fascist points far better than China currently does. China is certainly more liberal than it was under Mao, but it's not fascist.

Because the trend is clearly not to zero currently, there's a lot of rich people (and the number is growing), profit is still growing, it's just that the gap between poor and rich is also growing. But Capitalism doesn't care about a lot of poor people. How that will be long-term is another story (as said ecosystems are the limiting factor).

The tendency for the Rate of Profit is falling, and will do so even when rich people grow and gross profits rise. Capitalism does care about poor people, wages are tied to subsistence + replacement (child raising), but it will pay no more until Capitalism is abolished. It is, in fact, this vector that drives decay and decline, wages cannot increase beyond it except in low supply labor fields. You may want to read Wage Labor and Capital