This is happening now too with my 4s with ios7. It acts the same as my old 3GS during the ios5? updates. I fear that my 4s won't be able to handle ios8. I don'

This is happening now too with my 4s with ios7. It acts the same as my old 3GS during the ios5? updates. I fear that my 4s won't be able to handle ios8. I don't expect Apple to support phones forever, but why does something like texting/inputting into a keyboard get worse and worse as the life of the phone goes? Doesn't seem to make sense.