I think it depends on how good you are. If you're a great developer, with deep knowledge of patterns, a strong commitment to refactoring, with lots of experience such that you're aware of the pitfalls you are likely to befall, then you're probably right: frameworks will buy you little.
I'm pretty good, but I'm apparently not good enough, because I find myself consistently learning things from frameworks. I certainly am familiar with the Last Ten Percent you're talking of. But I also know that for every 10% that I have to pull teeth to get, there are many many things that work well because the platform team did a great job and drew on a depth of experience and expertise that I just don't have yet.
DHH built a lot of Ruby apps before he built Rails, and by using Rails I can draw on his experience. As a solo founder that's worth a lot to me. And even now, when I've largely moved on from Rails I still draw on things I learned from studying that framework. And the frameworks I use now are equal distillations of very deep experience.
You're perhaps a more experienced developer than I am, or just better suited to the job.
You touch on one of the other benefits of a framework; they're a fairly decent way to learn. But, unfortunately, much of that is because you're learning what NOT to do.
A much better way to learn is to go write your own framework. Then you're forced to encounter the pitfalls and overcome them through research, trial-and-error, and interacting with the community.
But continuing to use a framework is just a crutch in my opinion. At some point not only are you not learning anything but, as I mentioned before, all you're really doing is gluing framework code/modules together. You're actively doing yourself a disservice and letting your skills atrophy by relying on such a crutch.
One thing about frameworks that I find interesting is; how many were used to develop Unix? None. Because there weren't any back then. And now its in billions of devices worldwide.
I did this myself. It was crap. Fun to write, and I learned a lot from it. But still, monolithic, poorly documented, tightly-coupled crap and even I don't use it anymore.
I'm pretty good, but I'm apparently not good enough, because I find myself consistently learning things from frameworks. I certainly am familiar with the Last Ten Percent you're talking of. But I also know that for every 10% that I have to pull teeth to get, there are many many things that work well because the platform team did a great job and drew on a depth of experience and expertise that I just don't have yet.
DHH built a lot of Ruby apps before he built Rails, and by using Rails I can draw on his experience. As a solo founder that's worth a lot to me. And even now, when I've largely moved on from Rails I still draw on things I learned from studying that framework. And the frameworks I use now are equal distillations of very deep experience.
You're perhaps a more experienced developer than I am, or just better suited to the job.