That's not true at all, this is a myth in the knife industry and I don't understand where it came from. If you have a big thick knife, it's gonna be incredibly "tough" no matter what steel it's made with compared to a thin, slicey one.
Take the Esee 5 for instance, a knife that is touted by some to be indestructible and is made of 1095, a steel which toughness wise scores lower or about the same compared to many CPM stainless steels that you often see people complaining about chipping in their super thin folders. People often wrongly attribute the toughness of knives made in 1095 steel to the steel itself, when in reality most 1095 knives are heat treated quite soft (55-58 HRC) and are pretty thick to boot. A thick knife doesn't have to worry about using a super tough steel because a quarter inch thick piece of steel like the Esee 5 is gonna be tough to mess up no matter what steel you use.
A thin, slicy knife on the other hand would benefit from a tougher steel like CPM-3V, Cru-Wear or even magnacut because it doesn't have that same structural strength as a thicker knife, you can grind a knife way thinner and still have a very stable edge using a tougher steel, I would take a 0.09" thick knife in magnacut over something like S90V any day of the week because I know I'll have far greater edge stability and less issues with chipping using the magnacut in a knife with such a thin blade stock.