Piling on. It's easy to be dismissive when the resulting design is so uncompelling. It can't accomidate the existing needs, but the existing needs are compelling enough to leave the old version, likely for at least a decade.

If the new design was adequate, it would probably be adopted in a release or two. If it were better, there would be demand to get it to all the well used components. There might still be some components left behind, there's a lot of components.

A truly inspiring design might pull everything forward automatically... But that's asking a lot.