On investigation I see he also opines at length on economics and politics, also outside his expertise. My own equally-qualified opinion is that we don't have f

On investigation I see he also opines at length on economics and politics, also outside his expertise. My own equally-qualified opinion is that we don't have flying cars primarily because we don't want them very much. As people richer they spend an increasing share of their income on services (e.g. eating takeout instead of making our own food), on intangible positional goods, such as living in sought-after neighbourhoods (sometimes in worse material circumstances) and wearing fashionable clothes (which are often poorer quality than no-name equivalents), and on seeking to control the behaviour of others (e.g. homeowner associations in the USA).