When you put it this way, it makes perfect sense. My first computer C64 came with Basic pre-installed and that's how an eight year old learned to code. I guess the equivalent would be, that there would a button 'code' on the browser UI, and that would lead the user onwards.
Dev console is a debugger, not a code editor. It's useful for us to assist in developing web applications. It's far less useful for a non-engineer to tinker around with and make simple things.
You can't install npm packages. There's no simple UI to alter DOM like via drag and drop. Theres's no pre-built components (besides html) to easily create more advanced functionality. They have to write JS from scratch to add events. Managing more than 1 liners is a pain.