This is something that this series makes canon about the video game Eggman

The reason he fails is that he DOESN'T think his plans through

He's got a genius IQ but all the patience of a man who thinks the time it takes to microwave a burrito is too long to wait

He comes up with an idea like "Let's free a chaos monster from a sacred gem" or "Let's make an alliance with a top secret weapon my crazy grandfather built" and then never plans through how it will go he just wings it