The analogy is (of course) imperfect. There's an element of risk and stochasticity in climbing the hill; you might fail, or you might realize you're actually doing the wrong thing.

If you stay at the bank, or at a nice job, you're almost guaranteed to continue that gradient ascent. It's not the case with a startup; it's not as simple as deciding to do it, having to deal with a local minimum, and then continuing upwards.

Many want to be at the top of the hill. Few want to take the risk of actually climbing it.