I think BTC resisted the BCH rise over the weekend because the block difficulty of BCH spiked, making it less profitable to mine. Otherwise the BTC chain would have never had the hashpower needed to keep going... Ironicaly BCH Difficulty Adjustment Algorithm "saved" BTC. The DAA has evolved on BCH since nov 13th hardfork and it wont be that way anymore. If BCH price rise too much it's ok, but I'm not sure BTC can resist a new rally to BCH without a change in its own DAA via a hardfork, it's too slow to adapt atm