I think a lot of these grid systems and layout libraries are overkill, and in turn, make the designs they are being used for, more complicated than they need to be.

Sure, it would be great to have a more component focused tool for FE development, but I think creating separate, fixed-width designs for tablet, phone, and desktop, with containers does the job fairly well. When the designs try to resize components for every use case you get more headache than it's worth.