Do they pay soccer players even though they don't play?
Yes and no - there is no contractual requirement to pay the
players. For example, FIFA pays the FAs of the countries that play
but those FAs have no obligation to pay the players and FIFA does
not mandate that the players get paid by their FAs.
Like the Rugby World Cup, the Football World Cup prize money is
designed to develop the game in the country of the winner, not
specifically to pay the players. But because established countries
like Brazil, Argentina, Germany and Italy are often winning the
World Cup, those countries don't need to develop game with that
prize money so they tend not to. They pay the players incentives.
There are no set payments and no "salaries" for the players.
So while the short answer to this question might be yes, the
technical answer is no in terms of knowing what they'll get or that
they'll get anything at all. That is, players do not go to World
Cup knowing they will get paid or knowing how much they will get.
It's not like their club agreements where they know they will get
150,000 pounds a week.
The reality is that if you told World Cup players that they
won't get a dime, the great majority would go happily. The World
Cup is not about getting paid, it's about winning the World
Cup.