It's a tradeoff. There are already keyboard shortcuts for 'previous page' and there will be extension support to re-add 'backspace as previous page', it just won't be on by default.

If you were a drugstore and had a drug that was functionally identical to aspirin but caused day-long projectile vomiting in 99.96% of people who took it, would you think it was a great idea to hide the aspirin in the back and give the drug that is almost guaranteed to cause harm to someone as the default?