Yes, different interests. No matter what people would like to think or say America does retain a certain amount of "Exceptionalism," we are not and most likely never will be a socialist country. It is not a part of our culture. Yes, we will introduce certain socialist policies like Social Security, Medicaid, Medicare, minimum wage, and a form of Universal Healthcare but we will never transform into a truly socialist country because it runs directly counter to the American experience.
America was founded on Puritan values, now I'm not talking about religious views but a certain ethic that "hard work" will yield you just rewards. It's about a certain amount of independence, to be the master of your own destiny. And, that is why capitalism has always been at the heart of our politics. While we recognize the need to help those who cannot help themselves even a majority Democrats would balk at the notion of giving away "something for nothing." Our social policies are designed as stated before to help those who can't, for whatever reason, help themselves but those who can work and provide for others are expected to pull their fair share.
This is why so many immigrants emigrate to America, the chance to make something of themselves. They believe that if they are committed and work hard they can build themselves a better future. It's also why so much innovation takes place here. If you remove the incentive for others to work hard then innovation and industry will stagnate.
So, while I'm all for universal healthcare the notion that America needs to be like Canada or exactly like any European country is just nonsense that devalues the inherent separate culture that is America.