How did Republican pro-business policies encourage economic growth in the 1920s?

The 1920s are considered to be a time when the government
pretty much got out of the way of business and allowed it to operate as it pleased. 
Conservative historians, in particular, believe that this laissez-faire attitude is what
encouraged economic growth.

For example, the Republican
governments of the '20s did not do much to enforce the antitrust regulations that had
been put in place by the Progressives.  This allowed businesses to increase in size and
to, therefore, become more efficient.

In addition to this
sort of "hands-off" attitude, the Republican administrations also cut taxes of all
sorts.  Economic historians argue that this gave people more of an incentive to work and
to invest.  By doing so, they argue, the government promoted
growth.

The 1920s are seen, especially by conservatives, as
a time that shows how important it is for government to cut taxes and regulations. 
This, they say, caused the economy to grow in the 1920s.