With Steve Jobs gone, is American innovation past its peak?

Pardon the ponderous headline, but the question is worth asking. From Greg Ip in the Economist:

Americans' entrepreneurial self-esteem is now embodied by Apple, Google, Facebook and Amazon. These are indeed fabulously innovative companies with world-beating business models. Yet one wonders if they are increasingly the exception, not the rule, and if the passing of Mr Jobs is simply the most prominent example of a broader decline in American entrepreneurship. According to JPMorgan, in the late 1990s, employment at start-up companies regularly grew 1.2m per quarter. That has fallen to 700,000 since the current recovery began. John Haltiwanger, probably the leading economist on employment dynamics by firm size, finds similar trends. Entrepreneurship and innovation, of course, are not the same thing. Yet even if American innovation is fundamentally sound, there remains the more unsettling problem of how narrowly its fruits are shared. If you want to know why the Senate is on the verge of passing a bill punishing China for its trade practices, look no further than this fact: Apple, Google, Facebook and Amazon collectively employ just 113,000 people, a third of GM's payroll in 1980.