Nordics do not practice socialism but very high levels of taxation and redistribution. They are highly capitalist economies.  The reasons that they can achieve this state are that

  1. Northern europeans have been selectively eliminating the troublesome lower part of the gene pool for thousands of years (impulsivity and IQ under 80.)  Cold weather, short summers, darkness, manorialism, lots of hanging, no immigration from north Africa, Levant,  central Asia, steppe, or Asia to damage the gene pool.)
  2. These are very small countries.
  3. They have no diversity to create political conflict over redistributed wealth.
  4. They have no competitors on their borders to meaningfully defend against.
  5. They are bordered by near kin who have similar values and are not competitors.
  6. They are educated protestants exposed to Hanseatic and pre-Hansa cultures for many centuries.
  7. Northern european women have been able to use property and breed late for centuries.

(BTW: I get very tired of these fake questions dreamed up by paid workers in india in order to generate clicks.)

https://www.quora.com/What-are-the-key-differences-between-Nordic-socialism-and-other-flavors-of-socialism-and-is-there-an-example-of-nation-that-has-prospered-under-it