Sorry (and apologies for a tangent completely unrelated to the OP), but this is a terribly reactionary way to view web technology. Moreover, it ignores what was

Sorry (and apologies for a tangent completely unrelated to the OP), but this is a terribly reactionary way to view web technology. Moreover, it ignores what was an endemic problem in web design up until the proliferation of responsive layout. If CSS had never become a layout language, sure. We could all be browsing on opinionated clients that render everything arbitrarily. But that's not what happened, and front-end people for much of the past 20 years instead wrote opinionated layout. These layouts generally assumed quite a few things, such as a landscape-oriented display and a certain resolution or point density. So yes, these sites were, as you say, made for computers, not for tablets – quite in opposition to the original, client-agnostic vision of the web. Modern, responsive web design attempts to bring the layout-oriented web closer to the client-agnostic place it started by assuming fewer things about the client. You're advocating for more assumptions.