If blocks themselves had a proper server side registry (much like register_post_type, register_taxonomy) where the full block attributes were registered, sanitize callbacks for saving blocks, etc, we could have many different versions of UIs that interact with blocks. Gutenberg could be just one version of interacting with blocks.

I wrote about this in 2017 in this issue: https://github.com/WordPress/gutenberg/issues/2751#issuecomment-330930741

"Let's be honest. Gutenberg is not going to solve everyones's problems. No matter how awesome it is or will become, it simply will not meet everyone's needs. There will still be a market for creating content in different ways. Page builders currently completely dismiss the Post Edit screen, and these alternative post creation solutions will continue to exist post-Gutenberg.

With a solid Server Side schema, hopefully the Page Builders could at least start to adhere to a standard way of interacting with "Blocks". . .that way, if Page Builder A thinks using Modals to edit content makes more sense than the fixed-right sidebar of Gutenberg, they could build their own UI to interact with Gutenblocks, but still ensure the blocks are saved in the same way."