The idea that in a nation like ours that consumers and producers are free to share a mutually beneficial [and voluntary] market relation without a bloated, overreaching government intervening will create a more competitive and consumer-friendly market.
Tired of corporations? The notion that more regulation [which comes with more fees, taxes, and wage hikes] will inherently fix the issue (i.E the solution to big government is more government) is flawed by its nature. Nothing our government can do will stop corporations like taking their hands off of the economy.
Consumer confidence is at its highest level in 15 years after Donald Trump is elected president of the United States. People expect good things for businesses, their personal income, and employment with Trump as president. Deregulating pars of the economy is typically seen as positive for businesses, and people expect the economy to benefit from stronger American businesses.
Donald Trump's plans to deregulate parts of the economy have the potential to go either way, but it could encourage growth in those industries, meaning more jobs, more products, and more money being put back into the American economy. By deregulating it will allow industries some breathing room and allow them to expand and grow without needing to jump through governmental hoops as well as encourage companies to remain in the US when they would have otherwise looked to moving to another country to avoid the regulations along with the higher cost of labor in the US.
If you look at England as an example, deregulation has done nothing to solve their economic problems. Deregulation of their railways has lead to ticket costs almost tripling the normal level of inflation, pricing many people out of their own jobs. While too many regulations can be harmful, full deregulation can be even worse.
Deregulation will only lead to high profits for the rich, at the expense of the poorest people in the country. People are greedy, whether they are at the top of the food chain or the bottom. This is why many industries are regulated despite the fact that we want to be able to be free.