TI is definitely the largest player. Why shouldn't market consolidation by TI be questioned?

Diversity may also be misperceived, as the companies may not compete directly on all product lines. If you need a chip for something, there are times when it is only produced by one company.

Here are a few quickly-Googled numbers:

  TI
  Revenue: $13.966 billion
  Net Income: $3.228 billion

  ST Microelectronics
  Revenue: $8.465 billion
  Net Income: $1.131 billion

  NXP Semiconductors
  Revenue: $5.44 billion
  Net Income: $1.823 billion

  Infineon (Siemens)
  Revenue:$4.688 billion
  Net Income: $937 million

  Freescale
  Revenue: $4.46 billion
  Net Income: $1.15 billion

  Analog Devices
  Revenue: $2.8 billion
  Net Income: $712 million

  ON Semiconductor
  Revenue: $2.131 billion
  Net income: $395.8 million

  Maxim
  Revenue: $1.998 billion
  Net Income: $129 million

  Fairchild Semiconductor
  Revenue: $1.6 billion
  Net Income: $193 million

  National Semiconductor
  Revenue: $1.42 billion
  Net Income: $209.2 million

  Linear Technology Corp.
  Revenue: $1.17 billion
  Net income: $361 million

The US used to have a consistent anti-trust tradition. With Ma Bell reuniting and mergers like this, it seems to be waning.