The 29-year-old was speaking on the back of his national side's 2-1 loss to Italy in the Nations League third-place play-off on Monday (AEDT).
Both teams rested a number of players for the match at the Allianz Stadium, with Romelu Lukaku and Eden Hazard absent for Belgium due to muscular problems.
Courtois also played a full part in the semi-final defeat to France three days earlier and has questioned why his side had to face Italy in what he felt was a meaningless match.
"This game is just a money game and we have to be honest about it," he said in his post-match interview. "We just play it because for UEFA it's extra money.
"Look at how much both teams changed [line-ups]. If both teams would have been in the final, there would have been other players in the final playing.
"This just shows that we play too many games."
The international calendar is potentially facing further changes, with a biennial World Cup being proposed by FIFA's head of global development Arsene Wenger.
UEFA has already made clear it is against the plans and Courtois has added his name to a growing list of dissenters.
"They [UEFA] made an extra trophy [the Europa Conference League]… it is always the same," he said.
"They can be angry about other teams wanting a Super League, but they don't care about the players, they just care about their pockets.
"It's a bad thing that players are not spoken about. And now you hear about a European Championship and a World Cup every year, when will we get a rest? Never."
Courtois said: "In the end top players will get injured and injured and injured. It's something that should be much better and much more taken care of.
"We are not robots! It's just more and more games and less rest for us and nobody cares about us.
"Next year we have a World Cup in November, we have to play until the latter stages of June again. We will get injured! Nobody cares about the players anymore.
"Three weeks of holiday is not enough for players to be able to continue for 12 months at the highest level. If we never say anything it [will be] always the same."