10 Reasons Conor McGregor Vs. Floyd Mayweather Is More Likely Than You Think
7. Mayweather Thinks It's An Easy Fight

If nothing else, Mayweather may see a fight against McGregor as easy money, and an easy victory.
And if we're being completely honest, he might actually be right.
MMA isn't boxing. No takedowns, no kicks, no elbows. Hand position differs, since you don't need to worry about someone shooting in to drag you to the mat. Footwork differs. It's an entirely different sport.
Great strikers in MMA are often not great boxers (and great boxers don't often translate into great mixed martial artists). It's likely that McGregor will struggle in boxing. Mayweather will be on his horse the whole fight, staying out of harm's way. McGregor's biggest hope for victory would be an early knockout - he hits hard - but after that, well, his chances are slim.
Mayweather knows this. If enough money is on the table, he may just decide the odds are in his favor, and take the (calculated) risk and come out of retirement.