Assuming the country wants to import goods and services, then they are going to need to be able to sell goods and services. The desirability of the goods and services the country is selling can be roughly indicated by the population's purchasing power.
If more and more people are earning less, then that is not a good sign for the desirability of the country's goods and services.
No, the import ability of a country is indicated by the ability of the country to balance it's imports with exports, which are either real exports or are financial assets.
There most certainly is not a one to one correspondence of stuff to money.
If more and more people are earning less, then that is not a good sign for the desirability of the country's goods and services.