Under socialism, the employment pie is infinite. However the amount of funds available to the workers is finite and decreasing. It's up to the government to parcel out the funds.
This is actually more like communism. Under ideal socialism, everyone would produce to their capability and everyone lives happily ever after.
Not really. Productivity growth is generally negative, so each year it costs more in real terms to employ the same amount of people. Thats why places like Spain and Greece have 23 % official unemployment, and why the Soviet Union, which claimed full employment, actually had over 25 % unemployment (permanent unemployment insurance doled out to people doing no work).