Not really true in Rafa's case though. He built a great side capable of challenging the big 2 with Valencia and created the best Liverpool side over the last 20 years with his transfer dealings. I disagree with a lot of his tactics and his bizarre obsession with sports science, but he's still a great manager.
Its absolutely not true in Rafa's case when you look at those clubs. Rafa is a 4-2-3-1 man, he will play it in many variations but that is what he is. give him the tools and he will make one that is very tough to beat, (valencia liverpool) don't give him the tools, and he suffers (inter, currently chelsea).
Should be noted that 3 managers failed at Inter because if the state of the side before Stramaccioni got then playing well.