Without getting being philosophical let me try to help you if I can. My attempt to answer is around your query..
It's not necessary who writes good are good investors, some are and some don't make the cut. People write well because they like to, they associate pleasure with act of writing. A great example is a number of Trading Coaches have educated billionaire traders but seldom traded by themselves. It doesn't mean they cant trade, it's just they love to coach.
Being an investment entrepreneur as you have put across also to do with an act where you derive pleasure, very little to do with financial security and future. Same way millions and billions end up having full time employment career enjoying their jobs and life. They never became Buffett! Had they jumped to act of investment dreamt of becoming Buffett would have actually backfired. In reality Warren Buffett (not the person alone) is a culmination of sequential acts with single minded objective. Imagine a 10 year old Buffett was picking up race tickets to see in case they are not expired. Had he not been 72 Billion worth today, he would have been doing something similar to speculation, investing or associate acts what is he doing now.
Coming back to your financial security question depends a lot on your lifestyle than income. Most scandalous bankruptcy happened due to lavishing lifestyle than income.
To summarise yes you can dream of becoming an investor (full time) anytime anywhere. But make sure you love the work of investment. Money or financial security is outcome of plan, not a plan to achieve objective.
But again loving and doing an act of investment is a significant step which requires enormous self less efforts. It's not necessary for everyone to achieve financial security through investing.