Earlier quoted context omitted.
Wrong, it's extremely important. You're devoting the next 5+ years of your life to a single task. You're forgoing your programmer salary for the next 5+ years, which could easily add up to $300k - $500k in opportunity cost. Your forcing your wife and kids to come along for the ride. You're going to end up a world expert in a tiny niche that, quite possibly, nobody outside of academia cares about. You should have a pr…
This sounds a lot like you are telling us what you value in life. There are no rules in life and it's not a requirement to have your whole life planned out at every moment in time. Most people don't, including highly successful people. That's ok. What's important is taking advantage of opportunity when it is presented. If a goal of yours is to learn, then a PhD is a great opportunity for this. The value of the PhD is…
I've found that if people want to learn, then they will learn. You don't need a PhD for that, and the process of going through a PhD doesn't really teach you anything more than you couldn’t have gotten yourself. Passion drives someone to learn, not getting accepted into a PhD program.