Well... IP law has a pretty strong centralizing tendency. After all, it grants control, not cash, so those that have the ability to leverage that control benefit more. That's going to be true for any kind of state-granted monopoly, but it's particularly true where each instance (here: copying) is almost free, since each additional instance provides value at no cost - better to be large, then, and amortize the research costs. The commercial victor might not be those with the best technology, but instead those with the broadest sales network (and of course lots of other factors play a role, too).
More generally, the combination of incorporation and contract law also strongly encourages centralization: because negotiations are by mutual assent, those with better negotiating positions extract more of the added value from such agreements than those with weaker negotiating positions, and incorporation trivially allows bundling strengths with almost no downside.
Then there's the way the legal system is structured, which is extremely complicated: "red tape". That's a generalized barrier to entry; a kind of cost that doesn't scale with size. Given that legal costs are high, those that can't afford to take risks are going to be outcompeted by larger entities that can afford such gambles, assuming the merit is at least somewhat unclear. In extreme cases, even if a small company (or individual) wins a court case, they may nevertheless be the net loser because cases take long and cost of lot of attention and money - the opportunity cost of engaging is higher for small entities than it is for large entities (at least in general).
Some of those effects are probably intrinsic to any system of organization, but some of them are likely a historical quirk. I'm not sure which are which, though ;-).