This seems to be a view that is often trotted out. The Marshall plan did contribute to European reconstruction following the end of the War, certainly the scale of American foreign aid spending in Europe between '47 and '52 is astounding. A total amounting to approximately $31 billion. Although $31 billion is a lot of money (roughly $160 billion in today's money), to the 18 or so European countries that received it was of relatively minor economic significance.
Marshall Aid in Austria amounted to about 14% of its gross national income, a significant amount, but Austria proportionally received more aid than any other European country. In countries like Germany, France and England, the financial significance of Marshall aid was considerably less, but the lessening of trade barriers, regulations and international economic cooperation that accompanied it was considerably more important in future European growth.
In countries like Belgium, the Netherlands and Italy reconstruction was pretty much complete by 1946. West Germany's recovery was largely thanks to the relaxation of occupation sanctions, as despite the destruction of the war, German industry had emerged remarkably intact, but paralysed by infrastructure damage, and strict occupation policies expressly designed to prevent industrial reconstruction. For example, vital industries (such as ball bearing manufacture) had only suffered about 16% damage of tools and machines. The total war damage to German industrial stock amounted to at most, 23%, a loss which was considerably offset by the massive growth of Industry that was the result of the war.
Changing attitudes, and a general relaxation of sanctions and restrictions meant that German industrial reconstruction was mostly complete by 1947, and the main problem for West Germany was lack of food due to the breaking of the link between the more industrialised West, and the primarily agricultural East, which was under Soviet control.
The Marshall plan, as one of the earliest expressions of the Truman Doctrine, ultimately had less effect on the reconstruction of Europe, and more of an effect on the political future of Europe. It was the relaxation of European trade boundaries that was required by the plan that laid the groundwork for the European Union. The political effect of Marshall aid in France, meant that the Socialist Ramadier government decided that the West was more likely a partner than the USSR, and that aid was preferable to extracting reparations from Germany. For Britain, Marshall aid was only a small sum of money compared to the multiple large loans that were negotiated between the UK and the USA. (which Britain finished paying off in 2006)
In contrast, due to the apparent reluctance on the part of the USA to allow Soviet occupied nations to partake of aid, and American involvement in the Greek civil war meant that the USSR was increasingly suspicious of American intentions. Ultimately it also led to the escalation of tensions between the East and the West, the formation of the Eastern Bloc and the construction of the Berlin wall.
Marshall aid, and by extension the Truman Doctrine dictated the course of American intervention for the rest of the twentieth century. It led to America supporting governments that were decidedly undemocratic, and some were downright murderous. Leading to situations such as the ludicrous coalition that opposed the Vietnamese invasion of the Khmer Rouge governed Cambodia. President Carter when meeting Brezhnev in Vienna in June 1979 was critical that the 'Soviet Union encouraged the and supported the Vietnamese in their invasion of Kampuchea [Cambodia].' Brezhnev countered by arguing that 'the citizens thankful to the Vietnamese for overthrowing the abhorrent regime of Pol Pot.'