One persistent criticism of the tech industry is that it no longer works on big ideas. For all of Silicon Valley’s talk of changing the world, critics say, Google and Facebook mainly hire armies of coders to figure out how to serve you more relevant ads, while Apple and Amazon just want to keep selling you new stuff.

These are crude takes, but they get at the disillusionment with an industry whose recent innovations do not seem to have resulted in measurably more prosperous lives for most Americans. Yes, the phone you carry today is far more powerful than the one you had a decade ago. But if your wages haven’t climbed and your job is imperiled because of some of the very technologies in that phone, should you rejoice?

Matt Rogers and Stefan Heck say you should. Mr. Rogers and Mr. Heck are management consultants who have long studied how technology shapes business, and in a provocative new book they put forward the ultimate optimist’s case for why the tech industry might substantially improve most of our lives.