This will make things described in the original article even easier. The reason Candiru works is because Windows machines are general computing devices which g

This will make things described in the original article even easier. The reason Candiru works is because Windows machines are general computing devices which give users almost complete access to the machine. If you want a machine that malware cannot spy on, you want something non-general and locked down, like an Chromebook or iPhone or some other system with secure boot and mandatory code signing. There must be an authority that decides, “this is password stealer that must be blocked” vs “this is keyboard autocomplete handler and can be allowed”. This requires standardized interfaces, code signing systems, auto updates, solid security boundaries, distributed app whitelists - lots of complex stuff. You can decrease complexity a bit, but if you go too far, you will end up with systems which are easy to compromise and hard to heal.