On my many visits to Spain I take the opportunity to watch some local football on a Sunday morning [while wife is looking round the shops]
They play on 3g or astroturf mainly & the ball is invariably played on the ground with quick passing so ypougsters are brought up on this type of game from an early age
Perhaps that has some bearing on the game from this level & is built into the national psyche
Can't comment on Croatia or Belgium