Go Back With Backspace Chrome Extension
Just download this extension to get it fixed! Yes, the extension is legit. The page tells me it’s created by Google, so it should be safe.
That said, I’m among the large subset of users who do actually use the Backspace button to go back, and I admit I rely on the Are you sure you want to leave the page? Data may not have been saved” message to tell me I’m leaving the form I’m working on.
I know there are people who have lost data because of this backspace issue, but I find it really stupid that there has to be an extension for this in the first place. Also note that while this should fix most of your backspace not working issues caused by Chrome, there are some pages where it fails. Still, it’s a “solution” to a problem that should not have existed in the first place.