On the OS, there are valid technical reasons for explaining some of the gap. The networked OS idea from the 90s simply isn't great, and as computers became more

On the OS, there are valid technical reasons for explaining some of the gap. The networked OS idea from the 90s simply isn't great, and as computers became more powerful it became a non-brainier to make each one do everything and get rid of the unreliable network. But well, that's just some of the gap. The truth is that most of what the industry does is chosen by really stupid reasons (or some times raw corruption), where the people making the choice has no power to fix any problem, and the problems are kept there by people not interested on improving anything. If you want to research why the industry does what it does, you should study political science, not anything related to IT.