[mikko-apo]

There's nothing that makes internet somehow undo-hostile. But your observation about relational databases not having the support for undo is in the right track. Actually it can be expanded to most data storage mechanisms, sql, nosql etc. Out of the box many data storage systems don't support versioning and that guides the applications towards the "warn, overwrite, no undo" pattern. It's just a lot easier to do apps like that.

For many cases it would be better if the underlying data storage mechanism would support versioning. Image a CMS that's running on top of git. You'd have diffs, history, branching, merging, clones, tags and other very important features out of the box. Doing those features on top of a relational database is a lot of work, but with git you get them free.