The last time we had a Conservative Presidency and Congress was back in the 1920's; they ended a Depression in 18 months.
Reagan did not curtail government spending because he knew he had to work with American Jihadist known as "Democrats" who controlled Congress and I'm so sick and ******* tired of stupid ******* morons pretending they don't know that Dems Controlled Congress during the Reagan years.
The OP was not ignorant of that fact, nor am I. The source in the OP comes from a libertarian institute, which is incredibly pro-free market, as am I. The point trying to be made is not that Reagan is some evil terrible president, the point is that government did not decrease under Reagan's presidency. Whether he wanted it to or not is irrelevant to that point.
Conservatives hail Reagan as the man who decreased government, spending, and taxes. They say his policies caused a period of economic growth unprecedented in history. Liberals point out that what actually happened in the 80s was an expansion of government, and say that is why there was growth. That too is wrong. The growth was caused by a complete reversal of Federal Reserve Policy. Money was destroyed, not created, and interest rates were allowed to rise to levels closer to the natural rate.