GameMaker filled a very specific niche by targeting indie devs with little-to-no coding experience and giving them enough support to make a game (similar to Flash). Maddy Thorsen used GameMaker for Jumper all the way back in 2004, which was really an amazing game that has similar game play elements to her phenomenal game Celeste.

I'm not sure exactly what Godot's niche is, making it harder for it to have breakout hits.