Welfare for the people has to come from somewhere, someone is going to get stuck with the bill. Since democratic socialism uses the power of the government (the government gun to the head) from whom this payment is demanded, it is fascism of a sort, when viewed from their perspective.
If you are looking for a change this significant to occur is such a sort time span, a lot of force is going to have to be applied to make it happen.
Think of an aircraft carrier that's going to have to turn around 180 degrees in 60 seconds. There's going to have to be a lot of force applied, a vector, to make that happen. Society has it's own form of inertia as well. Big changes take long periods of time. Yes, there's the occasional exception, but far more often than not, it's going to take quite a bit of time.
Of course, should the US change over to a Democratic Socialist country, we can expect similar performance, over all, as the examples of such in the EU.
Extremely high cost of living. High taxation to pay for the nanny state and the give away programs. Lethargic business and economic responses to changes in market conditions, an exorbitant cost of government bureaucracy, and all the rest. In short, the US and it's historical dynamism won't be anymore. We will have become Europe.
If the jobs are fleeing the US due to an already high cost of labor, what's going to happen when that labor costs goes even higher?
In the EU, it's the strong unions. Are the US unions up to the task? I'm thinking not, and I'm also thinking that they aren't honest enough to play that role either.