I agree that automatic form restoration would be very helpful, but there's a huge space between classic HTML forms (where this is "easy") and single-page apps (

I agree that automatic form restoration would be very helpful, but there's a huge space between classic HTML forms (where this is "easy") and single-page apps (where nobody really expects it to happen). That space is where complex, dependent-on-javascript-for-no-good-reason forms live. The kind often encountered when dealing with financial & public institutions. It's unlikely that automatic form restore is going to work for a lot of these (especially multi-step wizards & the like) so preventing an extremely common accident seems extremely prudent to me.