Nice read. We should always strive to work our way up on devices we support (i.e. mobile first).
Something I found interesting is the use of Grid Layout — https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Grid_Layout.
Unfortunately it’s only supported by latest browser versions, but maybe worth considering in the future if anyone wants to STOP, or at least try to avoid, using breakpoints.
Oh, and throwing in “carrot” too — http://cssgridgarden.com/