This is not tech bros. Capitalism itself is the problem. Capitalism always socializes loses and privatizes profits. Do you think that democrat bankers like Jamie Dimon don't run for government assistance at every chance they get?
This is not a problem of a few "libertarian tech bros". The capitalists run the show, they run the government.
"Capitalism would get your bank and their depositors bankrupt, end of story."
Except that's not capitalism. America is real, actually existing capitalism, and only poor people get bankrupt, not banks or bankers. Capitalism is not about fairness or justice or whatever ideal. Is about maximizing profits and exploiting wage labor. "Socializing" loses maximizes profits, so that happens. Poor people getting bankrupt maximizes profits, so that also happens.
"It was the USSR that were using heavy machine industry to finance and subsidize unproductive companies, leading to monopolies and corruption."
I'm not sure what the argument is here. Nationalizing industries is not socialist per se. But you said it yourself "subsidize unproductive companies". So the objective was not to maximize profits, but to protect national interests and the development of socialism. Also, the USSR has a long and complicated history, from Lenin's War communism to NEP, to rapid industrialization, to perestroika, to liberalization. So we can't make sweeping generalizations.
But is unfair to talk about "monopolies and corruption" if you look at "western democracies" today. Monopolies. You realize that today only 5 or 6 companies (Unilever, Nestlè, Pepsico, etc.) control the vast, vast majority of food in the world? And "corruption". Corruption is legalized in the USA and banks and tech companies freely decide what the government should or should not do, get tax cuts, grants, subsidies, low-interest loans and so on. That's corruption through and through.
This is not a problem of a few "libertarian tech bros". The capitalists run the show, they run the government.