It seems to me that US trust busting in the past was:<p>1. Seen as radical at the time, and odious to all private industry.
2. Able to leave shareholder value somewhat intact because they were simply splitting physical assets.<p>While I think 2 might be addressed by eg forcing Instagram/YouTube/etc to spin off, 1 would require the election of radicals to high office. Our political system has built in so many safeguards over the years to keep true radicals out of office that I just can't see it happening. Trump promised many things, but disruption of business was not one of them.<p>edit: What I see as more likely is regulations that preserve shareholder value and enshrine these companies as utilities, erecting barriers to entry so high that they become permanent monopolies, while (hopefully) slowly reigning in the wild profits.<p>edit 2: Facebook's current share price basically values it as a utility already, and given their slowing growth they might even lobby for such regulation themselves to staunch the bleeding.