That’s what CMS tend to do. They create slugs for tables (collections) and records (“posts”) are linked under each table.
And CMS prevent you to change the slug to guaranty that the permalinks (links to records) never breaks.
Wordpress for example propose many variants in the way you can build a URL to a record, but never the simple domain.extension/record-name
Reasons are various but the main one is this would prevent users to give the same name to different records in different tables. For example:
Now, other systems can perfom URL rewriting and display whatever they want in the URL, but that would be counter productive to display the same URL for different pages. Technically possible, but doesn’t make a lot of sense. URLS shouldn’t be use like titles, even is a “clear URL” (a URL that you can read in human language) is a good practice.