One of the (many) arguments against socializing medicine is how, through usurping the price mechanism, it will invariably lead to rationing.
Whilst the most common example of this is that of waiting lists, an alternate example worth looking at would be on the amount of high end medical technology availiable, and benchmarking the number of units per capita with other similar counties. If the U.S has significant higher numbers of such machines, then it could indicate that rationing has occured in other nations, leading to a suboptimum outcome.
Data is most readily availiable for Computed Tomography (CT) Scanners and Magnetic Resonance Imaging (MRI) machines:
As can be seen, the U.S has has almost double the per capita distribution of OECD Scanners as the OECD median (14.8 to 34 per million people).
Next let us look at MRI machines, perhaps an even stronger indicater, due to their relative cost and shorter time since invention:
Here the difference is even more stark. Not only does the U.S have almost almost 4 times as many MRI machines per capita as the OECD median (26.5 to 7.1 per million), it also has more than any other country.
From this data, an argumant can definatly be made that the socialization of medicine may lead to a decrease in the supply of high-end medical technologies.