Many years ago I was a junior developer building cms-backed websites. I had the idea to recreate the database inside the database i.e. tblTables has lists of tables, tblColumns had columns with a tblTables.tableId foreign key etc. I thought it was clever of me to be able to edit the "database" inside the CMS. Except select were stupidly complicated and performance was terrible.
SPAs remind me of my "clever" idea. What if we recreate a web browser inside the web browser?