While the grid and flexbox have made things better, the display:grid is still not supported in IE 11 very well. The grid css model was implemented in IE very early but as the specification got updated, IE remained with a different(older and incompatible) implementation of display:grid. Of course, we can still make display:grid work in IE11 by some additional work. But this is an additional overhead.

Flexbox has very good support and consistent behaviour in all major browsers and for most of the time we can use flexbox model. With some learning for using flexbox and grid I could appreciate their utility. (though I do not use CSS regularly)

The state of CSS is very much improved and these days we don't have to depend on hacks like the float and clear in CSS. But, minor problems like the inconsistent behaviour of display:grid in IE 11 - make the need for a CSS framework relevant.