One of the more interesting theses advanced by Zero to One ^[1] is that monopolies are good to the extent that they afford companies the agency and comfort to engage in long-term activities:

Monopolists can think about things other than making money; non-monopolists can’t. In perfect competition, a business is so focused on today’s margins that it can’t possibly plan for a long-term future. Only one thing can allow a business to transcend the daily brute struggle for survival: monopoly profits.

If you accept this argument on its face, you can dither a little: sometimes these longer-term investments both involve value-generation and value-capture on behalf of the monopolist (the iPhone being subsidized by iPod's runaway success); sometimes they're purely altruistic, like Facebook's investment in open-source ^[2].

It's an interesting line of reasoning that essentially reduces down to "the area under the curve generated by a very successful business which would otherwise be eroded by perfect competition can be directed towards useful ends."

Finishing up Acquired's great two-part dive into the formation and breakup of Standard Oil, I stumbled into a useful (albeit anecdotal) rejoinder. They quote Ron Chernow in Titan:

While the old guard at 26 Broadway mourned the trust's passage, some Young Turks at the operating companies were overjoyed... One of these extraordinary mavericks, Dr. William M. Burton of Standard Oil of Indiana, thought that Roosevelt had performed an inestimable service. After the 1911 dismemberment, he said, 'It was felt all along the line—younger men were given a chance.' Burton patented an exceptionally valuable process in 1913 (two years later) for 'cracking' crude oil—that is, for refining it so as to yield a far higher percentage of gasoline. This discovery permitted Standard of Indiana to reap incredible windfall royalties.

Can you imagine a more useful counterfactual than "literally Standard Oil got better from both a shareholder and consumer perspective once they were liberated from the shackles of infinite market power?" I certainly can't!

Setting aside the much trickier discussion of whether or not market power can be amassed within a corporation without negative consumer-facing externalities ^[3], I find it difficult to argue that the safety of monopoly-granted market power outweighs the Darwinian pressure of a market outside of very specific circumstances. One right and responsibility granted to any successful company is to allocate their profits towards investments; it doesn't take a monopoly to be able to do so.