My belief is that you cannot separate success and personal development. They go hand in hand. Sure, you may be able to make lots of money without it but success is more than money. Success in my opinion includes many things that my mind would not have even been able to comprehend if it weren't for the people, books and seminars I made part of my daily routine. If you don't see the value in personal development, test it out every day for three years and make your decision.