If I am to provide a summary of why layout shouldnt be linear constraints, is that it can't faithfully represent content overflowing onto multiple lines. I.e. it's inherently one dimensional. I.e. you can't really have a layout that adaprts to the screen size without creating a lot of separate breakpoints. This is a big limitation, that for example flexbox doesnt have. When I left Grid i immediately went and reproduced a lot of stuff we've been doing in (new then) flexbox layout engine, and i was like: Oh my god, this is so much more powerful.