Why do carbon dioxide and sodium hydroxide not form sodium oxide and carbonic acid?

$\ce{CO2 + 2NaOH -> Na2O + H2CO3}$

as opposed to:

$\ce{CO2 + 2NaOH -> Na2CO3 + H2O}$

This is in the context of fractional distillation of liquified air, before which carbon dioxide must be removed using sodium hydroxide.