That's not the case. The neoliberal era of 1973 through 1992 routinely resulted in lower growth rates than the Bretton Woods era of 1950 through 1973 in essentially every region except Asia, which did not follow neoliberal proscriptions in the first place. Perhaps your estimate failed to account for population growth.
I am not sure where you are getting your data from to base your opinion, since you are not offering any, but you can calculate everything yourself.
You can download the GDP data from the St. Louis Fed here.
St. Louis Fed: Download Data for Series: GDPCA, Real Gross Domestic Product
You can download the population data from the Census Bureau here.
http://www.census.gov/popest/states/tables/NST-EST2008-01.xls
http://www.census.gov/popest/archives/1990s/popclockest.txt
In 1945, GDP was $1.7863 trillion in 2000 chained dollars. The population was 139,928,165. Per capita GDP was $12,766.
In 1975, GDP was $4.3112 trillion. The population was 215,973,199. Per capita GDP was $19,962.
Per capita GDP growth from 1945 to 1975 was 1.50%. (19962/12766)^(1/30)-1
In 2005, GDP was $10.9895 trillion. The population was 295,560,549. Per capita GDP was $37,182.
Per capita GDP growth from 1975 to 2005 was 2.09%. (37182/19962)^(1/30)-1
Your selection of 1973 is a curious one as no economist I know of refers to that as the beginning of the "neoliberal age," nor do I know of any conservatives who would argue that Jimmy Carter was anything like Ronald Reagan or Margaret Thatcher. The abandonment of the currency regime of Bretton Woods does not signal much other than currencies were allowed to float as the United States abandoned the gold system. 1973 was also the last year before a big recession while 1950 was the first year out of a recession, which is convenient for anyone data mining to make a political point as the data is end-point sensitive.
Business Cycle Expansions and Contractions
That is why I posted a graph going all the way back to 1870. Since 1870, GDP per capita has grown at a trend rate of 2.0%.
In 1980, GDP was $5.1617 trillion. The population was 227,224,681. Per capita GDP was $22,716.
In 2000, GDP was $9.817 trillion. The population was 282,171,936. Per capita GDP was $34,791.
Per capita GDP growth from 1980 to 2000 was 2.15%. (34791/22716)^(1/20)-1
Doing the same exercise, per capita GDP growth from 1980 to 2008 was 1.89%.
I forgot to add, using your time frames, from 1950 to 1973, GDP per capita growth was 2.48%. From 1973 to 1992, it was 1.80%. However, again, the selection of those time periods is self-serving since you are using selective data from different points of time on the business cycle. 1950 was when the economy was beginning to accelerate out of a recession caused by the end of WWII. Similarly, 1992 was also the beginning of an expansion after the economy was coming out of a recession caused by high interest rates and the Gulf War. A statistician would not use those dates but rather would corresponding similar points in the business cycle.