I really doubt you and you dont provide any details about your setup either. I have exactly the same issues as the poster. I have about 20 tabs and it is costing 1.7GB ram. Note that I almost never reboot, so it may well be leaks, but even so, on eventual crashes, reloading my tabs is painfully slow.
Mac El Capitan, FirefoxDeveloperEdition (which iirc is basically equivalent to Firefox Beta), not many addons (Tab Groups, uBlock Origin, No More 404s). I can screenshot my Activity Monitor if that'd help?