Sorry to put it like this but you are absolutely wrong. First you develop something that works, then you try to find ways to optimize it, especially in an emulator where you have to understand all the aspects of the emulated system before even trying to aim for performance. Your statement that "few emulator authors can be bothered to write dynarecs these days" also seems to be wrong, as most of the big emulators have one (Dolphin, PCSX2) and all the new ones (Citra, CEMU) are not yet in a state where optimization can be done.