Too bad, but thankfully this will largely solve itself. The need for so many themes becomes unnecessary when the header, footer and sidebar are all blocks in Phase 2 of Gutenberg. We can already see this when using page builders today with themes like the Beaver Builder theme or the Page Builder Framework–the themes generally act as flexible containers for the page builders.

We’ll also see this to a much lesser extent with plugins since plugins that purely manifest as content become blocks and generally only things that have management/need an admin settings page will stay as plugins.

Times are a changin.