You could apply the same thought process to clothing. None of my clothes fit me perfectly, because they're all bought off the peg. But they fit me well enough for it not to bother me, and buying custom-made jeans/t-shirts is just not cost effective for most people. There is a market for custom-made frames, just like there are tailors who will custom-make you a suit. I think unless you have a really weird body, you'll find an OTP bike that fits.
You could apply the same thought process to clothing. None of my clothes fit me perfectly, because they're all bought off the peg. But they fit me well enough for it not to bother me, and buying custom-made jeans/t-shirts is just not cost effective for most people. There is a market for custom-made frames, just like there are tailors who will custom-make you a suit. I think unless you have a really weird body, you'll find an OTP bike that fits.