The big bourgeoisie are usually comfortable where they are. It’s the petite bourgeoisie that are squeezed between much larger and more powerful capitalists above them, threatening to swallow their market share, and workers that steadily gain more strength below them, threatening their bottom line.

There’s an interesting connection to antisemitism here. We’re very familiar with the antisemitic tropes of Jews controlling every big financial or media institution, which maps to the material reality of large capitalists always having the edge against small ones, but there’s also a lot of tropes about Jewish workers subverting their employers’ interests. This is related to cultural Bolshevism and similar narratives in the 20th century. Nowadays I think the closest analogue is the 4chan j**t meme against South Asians taking jobs in tech fields, or the anti-immigrant hysteria.

The point is that people in the middle of the class struggle are the most likely to be the base of support for fascism because they are the ones who stand to lose the most from socialist revolution (the ultra rich can just use their connections and capital to move to another country and still be ultra rich).