11 Bloom and others (2017) as well as Thompson and Spanuth (2018) discuss how it has become more costly to make technological advances.
See Nicholas Bloom, Charles I. Jones, John Van Reenen, and Michael Webb (2017), “Are Ideas Getting Harder to Find?” available at https://web.stanford.edu/~chadj/papers.html; and Neil Thompson and Svenja Spanuth (2018), “The Decline of Computers As a General Purpose Technology: Why Deep Learning and the End of Moore’s Law Are Fragmenting Computing,” available at https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3287769.