How can you be the Party of economic individualism, while changing on the role of government in the economy?
The Republican Party has consistently championed having government act in ways to increase the ability of people with talent to make use of such talents for their own benefit. What has changed over the decades is what is sees as the biggest impediment to such ability and the ways in which government can best promote it.
When it was founded, the primary threat to economic individualism was seen as slavery. Government could promote economic opportunity for individuals by doling out the public lands to homesteaders, providing for education (at the federal level via land grants for endowing colleges), and seeing to it that essential infrastructure such as railroads were accessible to all. Also in a purely pro-American vein, they favored having tariffs sufficient to block the competition from the cheap labor of Europe.
Today, the primary threat to economic individualism is seen as the burden imposed by government regulation and taxation. Government could promote economic opportunity for individuals by eliminating programs that encourage dependency on the government and generally reducing the costly role of government in favor of the more efficient private provision of services. They are also generally opposed to tariffs as harmful to the economy as a whole.