I think the willful blinkering of business interests toward only the .001 percent business that's exploding RIGHT NOW is a greater contributor to the fragmentation of business today than the fading priorities of WWII ever was. The idolization of the Gambler on Wall Street (or in SV) has misdirected our priorities away from respecting those who seek to build a sustainable business where normal people want to make a sustainable living. Now the prevalence of jobs at yet another ephemeral startup or large corporation awaiting it's next merger/buyout has greatly destabilized the workplace, much less made the job of corporate leader/ visionary/ innovator next to impossible. Instead of creative invention, corporate CEOs now focus instead on cost cutting destruction, and Wall Street applauds.
I wouldn't call that fragmentation so much as disintegration.
There used to be many thousands of such manufacturing-based small businesses in America. They tended to stay focused on their competency or branch out tentatively into related products, flexibly grow and shrink to meet demand, or sometimes get acquired. But I don't think many of them planned to become the next General Electric.