Republicans have long had the support of small businesses, and it is clear that many of their nuts and bolts policies appeal to business owners small and large. While they make a big fuss about abortion, immigration and terrorism, making many terrible missteps along the way, they still have the back of businesses, but that is only a good thing for the business owners and not for their employees (other than giving them a job).
It is not widely reported, but several journalists, most notably Chris Hedges ("American Fascists"), have attended lower level, grass roots rallies for Republicans. What they saw and heard is frightening to me, but it is clearly the basis for much of their economic policies. These are things they will deny to their deaths, but they are all too true.
First, you will rarely hear a Republican official encouraging higher education as a right, or working to increase college attendance. The Republicans want the vast majority of citizens/potential employees to be ignorant/poorly informed. Education is fine for the management class/ownership class, but it is better to limit how many ideas employees and laborers are exposed to. It is not as extreme in the US now as it was in the USSR after WWII, when Stalin sent large numbers of Red Army servicemen to the gulag or killed them because they saw how well people lived in Germany and western Poland as they stormed across them, but it is an underlying principle of Republicans. One huge reason is the religious right is very worried their children will see their beliefs as the bullshit they are once they are educated (especially at the "leftist, secular humanist universities"). Another reason is an uninformed voter is their greatest goal. It is much easier to convince someone unlikely to read the New York Times or the New Yorker the Republican way is the best for them. Third, and most important for business, is poorly educated workers are felt to be easier to control and manipulate, and they will also have fewer options for employment and will likely stick with a less than optimal job rather than take a chance on something new.
So, that brings us to the next Republican platform plank on economics: keep wages low. They will NEVER support an increase in the minimum wage. All the benefits of any hard work by people should be reaped by those who manage them or own the business in the Republican world. This aspect of capitalism, the aspect that makes workers want to unite in order to bargain for better wages and conditions, is kept in place by making it very hard for them to unionize, another economic plank.
You will also rarely find a Republican leader in favor of any environmental or workplace regulation. There are really only three targets of environmental regulation: 1. businesses that make or destroy things, including power generation, the military and loggers; 2. farmers; 3. People who kill animals. I would be willing to wager you wouldn't find more than 20% of any of those groups who would vote Democratic routinely. It is a lot easier to make huge profits if you can just throw your waste in a nearby stream, as GE did routinely in its ascent to the top. You can raise even more hogs for the money if you don't have to worry about where all their waste goes (they make a lot of waste). So, businesses like Republicans because they care way more about profits for their donors than the environment.
Republicans are always in favor of tort reform. Without regulations or proper enforcement of regulations by underfunded government agencies, the only recourse to bring a problematic business or polluter in line is the judicial system. While frivolous suits abound, there are way more very serious attempts to hold bad citizens and corporations responsible for the terrible things they do to their workers, the environment and their customers. A successful lawsuit can be the end of a business, especially before it gets big enough to afford lobbyists.
That brings us to the next point. While both parties are guilty of rewarding their donors with favors (it is estimated that donating to and lobbying politicians and political parties is one of the most lucrative investments, with a return of 100:1 on most efforts through changes in policies, especially tax protections and loopholes, avoiding regulations, and protections from imports), Republicans are notoriously susceptible to lobbying from businesses and the influences of very conservative business groups like the U.S. Chamber of Commerce, which is almost always on the side of businesses small and large.
Finally, Republicans can hardly be bothered about the poor. Sure, an individual case will touch their heart strings, and they tend to donate to charities (primarily their churches) and rely on them to care for the poor and hungry, but the mass of people in poverty is much easier for them to ignore as Republicans are almost uniformly right wing authoritarians, people who share certain thought patterns and beliefs (it is not technically a personality type, but it is easily tested for - see Bob Altemeyer's research - and reference my short but thorough essay about them a few articles down in this website). Among these patterns and beliefs is a lack of concern for inequality and a fear of people different than them. They actually prefer inequality in most cases, with the most glaring recent example the struggle of Republicans to keep any form of universal health care from passing. Even the bill that passed, which was basically a handout to the insurance and pharmaceutical industries, both big Republican donors, was a massive affront to the Republicans because it helped people who otherwise couldn't afford it get access to health insurance, something they felt should be a reward for being a good, obedient, hardworking citizen who supported Republican interests rather than a human right.
So, The Republican party has as its backbone policies on economics keeping a large segment of the population poorly educated, poorly compensated, working in potentially dangerous and difficult settings for businesses and employers who don't have to worry about their effects on the environment or safety, and having the government do as little as possible to help them advance or even survive, all in order to maximize profits for business owners and the management class. That is what it means to be "pro-business" in the U.S.A. in 2016. Policies like these make people angry. The smart and well-informed will gravitate to someone like Bernie Sanders, who points all this out and wants the system changed, and the less well-informed and authoritarian will gravitate to someone who places the blame on someone else, like undocumented immigrants, President Obama, and maybe even the Jews.