SBD is now $7 and STEEM is 50 cents, barely higher than Hive. Steem has gone out of their way to break SBD again, and it hasn't helped the price of STEEM the way you suggest.

You are confusing cause and effect. Both STEEM and SBD went up a lot in 2017-2018 because there was a tremendous spike in speculation and demand throughout the crypto market. It wasn't a matter of SBD going up being the cause and STEEM going up being the effect, they simply both went up.