If you haven't noticed Goku only dies so he can have most intense training there is... There is a difference between dying and then returning stronger then ever and staying dead forever as he would have if Frieza have killed him.
Yes, because of one page

. Whats difference if there is one or 50 pages that prove it wrong?
There are none things against multiplier theory. After all power increases are about multipliers - Oozaru, kaioken...