1) There is no such thing as complete "socialism" or a lack thereof. Technically, anything that the government does for the broader good is a form of socialism. So the socialism we talk about is a philosophy, not a form of government. For example, the United States actually operates under many socialist programs and such; it just isn't labeled "socialist" overall relative to how socialist other nations are.
2) Scandanavian-style socialism and its success only indicates that it works in those countries. Bernie Sanders is fond of referencing this success, but he is committing the logical fallacy that what works in one place is sure to work similarly in other places. The United States varies in many, many ways to the referenced Scandinavian nations, including in demographics, size, and economy; any direct application of Scandinavian socialism in the U.S. would probably fail in an ugly, spectacular way.
What works for some won't work for others. What the United States has undeniably gotten right (as right as can be done) is implement multiple branches of governance under a system of checks and balances, which allows the country to be dynamic and flexible. Change can take time, and mistakes can be made, but the people are more protected than under just about any other system. If it would be good for the nation to turn more strongly towards socialism, it would likely happen over time, and if it would not be good, it won't go there.