Big-government advocates will say that as society grows more complex, laws must multiply to keep up. The opposite is true. It is precisely because society is unfathomably complex that laws must be kept simple. No legislature can possibly prescribe rules for the complex network of uncountable transactions and acts of cooperation that take place every day. Not only is the knowledge that would be required to make such a regulatory regime work unavailable to the planners, it doesn't actually exist, because people don't know what they will want or do until they confront alternatives in the real world. Any attempt to manage a modern society is more like a bull in a darkened china shop than a finely tuned machine. No wonder the schemes of politicians go awry.
F.A. Hayek wisely said, "The curious task of economics is to demonstrate to men how little they really know about what they imagine they can design." Another Nobel laureate, James M. Buchanan, put it this way: "Economics is the art of putting parameters on our utopias."
Barack Obama and his ilk in both parties don't want parameters on their utopias. They think the world is subject to their manipulation. That idea was debunked years ago.
I’d add velocity too besides complexity. Transactions move at clips far too fast for the regulators to comprehend. I recall listening to an Econ lecture in the 1970s about the coming role of computers in banking. My Prof (and I) thought these machines “a natural” for planned command style economies like the Soviet Union. Yet it was the velocity of computers in the information age that brought them down, and propelled the free world ahead.