Where is that figure from? You're probably looking at mining pools, which don't actually own the hardware - individual miners do. A pool is just a service that coordinates many miners to work together and split the rewards. If a pool tried to behave maliciously, miners would simply switch to another pool and the pool would quickly lose its hashrate.
Competitive ASIC miners are manufactured by only a few companies. It's not inconceivable that they could use TC to lock them to specific pools or simply refuse to sell ASICs to the general public.
