Technically there's no reason an EV Miata couldn't have a manual transmission, it's just that auto manufacturers so far have largely decided they'd rather just

Technically there's no reason an EV Miata couldn't have a manual transmission, it's just that auto manufacturers so far have largely decided they'd rather just opt for a more powerful motor than deal with the drive train complexity, weight, and friction losses of a transmission. I don't expect Mazda to make a manual transmission EV Miata but it's something they could do if they really wanted to.