Why not make it your goal to find a goal?
Due to hedonic adaptation, the journey of working toward something is usually more rewarding than reaching any particular destination, especially if you're getting lots of feedback along the way.
Also, I've spoken with literally thousands of entrepreneurs, and most don't have what I'd describe as "killer instinct." Many of them gained a purpose through their business, rather than starting their businesses to satisfy some pre-existing purpose. It's a bit like how people find a new mission in life once they have a child.
What we think impacts what we do, but perhaps less obvious is the fact that what we do impacts how we think. Sometimes the first step is to throw yourself into a situation and then allow the motivation to come.
Finally, I'd say I'm an abnormally driven and goal-oriented person, and even I often think about my inevitable death and the purpose of it all. I think it's just part of being human and thoughtful.
I've come to the conclusion that living a good life is largely about being proactive. We like to think that given enough money and freedom we'll all do things that make us happy, but instead we tend to stagnate. It's easy for anyone to settle into simply letting the days pass: whether you're single or in a relationship, an employee or a founder, traveling or stationary, it doesn't matter. You can get into a routine of simply doing the least effortful thing.
For most of us, being proactive about living your life in a fulfilling way requires effort, the same way work does.