For Franklin, Michael (Organized but Betrayal) and Lamar (Chaos but Loyal) represented two balances. Franklin saw Michael & Trevor at first as a revelation, a chance to work with professionals to make money with people who were committed. When you spend all your life with Lamar, it feels like another get-quick rich scheme that will blow up.
So no, he wasn't wrong, plus it taught him too of when to stop. He saw the horrors of trying to continue this life by friends betraying each other. Yet he knew Lamar despite his chaotic nature would always be loyal to him.