You are not crazy to give it up. I can't speak from experience; I am in my early 30's and gave up a lower rate about six years ago to good result, but that's just anecdotal. It seems to me you have a very strong position: You have serious industry experience and, from your description, very strong financial responsibility. It's almost irritating that this should be impressive, but it is: You are a whale among greedy remoras. ;)
It is certainly obvious to you that this is a risk. Being single and without dependents does help, but that also brings to mind the question of priorities. You're in a position, now, where you earn enough to wrap up your retirement reasonably early, if this pace keeps up. If that is what you want, then you might consider that starting a family -- if that's a priority for you -- could actually make your current income sources very, very valuable in a meaningful sense.
If your primary goal is work satisfaction... then yes, I would say this is an excellent opportunity to step out of your current environment (calling it a rut or anything else would paint a biased picture, I think) and potentially do something more rewarding, in terms of personal fulfillment. I would not go into such a venture with the expectation of more lucrative results, though. You seem to be in a good position. There are certainly many startups that succeed, and that won't change. But the reality will always be that more fail.
Be careful. You are in a good position, and you seem to know it. My suggestion would be to try and decide what it is you would be happiest doing, or at least deciding on things you want to accomplish. If you can manage that, then you will at least have something interesting to work towards. If not, then you may need more time before you can do something new and expect it to end well or at least satisfy you.