If miners stop playing stupid games and really want the best for bitcoin, they would stop stomping on the hardfork drums of war, and they would activate BIP141 as they have been told by everyone worth listening to in the space. But what happens when you give stupid janitors the ability to vote on engineering matters? that they will don't do the right thing.
Enable segwit with no stupid hardfork drama, and see bitcoin skyrocket.
Break bitcoin in half, see the price crash, and see everyone involved in the forked chain going bankrupt, with the price going to 0 on Forkcoin, and with Bitcoin crashing but going back 3 years in price and taking another 3 years to recover.
Your choice.
It's very hard to predict the impact of some event on Bitcoins price. For example, when there was the halving last year, the price almost didn't change on that day, so maybe our recent price rise to $2500-$3000 was because of the possible segwit activation, and when it will get activated, the price won't change much. As for miners, they seem to try to strong-arm Bitcoin community into supporting their decisions, but in fact they don't have the real power, because they will always be mining whatever is the most profitable, and what coin it will be is decided by the market.