In many cases you shouldn't need a computer, and for many where a computer is helpful, a very simple one should be possible which can use less power and with small enough ROM and RAM, and not needing any Wi-Fi and stuff like that. You also should not rely on computers too much even in the circumstances where they are helpful.

I do think that different computers (and other stuff) can be made which do not use proprietary software (and which do not use excessive software; I think it is also important, for a different reason). Free open specifications can also be made, too. Many people don't, but it can be done (although in some cases it is difficult, for various reasons).