Driving the growth of big companies has been a shift in the way government does business. In the past, federal agencies would hold competitions for each project -- specific jobs for which medium-size firms could effectively compete.
Starting in the mid-1990s, government-wide contracts became more popular. Generally, the contracts are so large that only big companies can compete for them. A recent example is the $50 billion, 10-year Alliant information technology contract, awarded earlier this summer to 30 companies, all but a few of them billion-dollar-plus firms.
This needs more examination.