Just look at the charts and the recently events that bitcoin had, everytime that bitcoin goes down, people buy bitcoincash and it goes up again.. Suddenly people move back again to bitcoin to buy at 500 - 1000 dollars less, they make a huge profit from that.
And then the same thing repeats, they earn a lot of money through bitcoin cash, a huge amount of money when they switch again to bitcoin.
It will keep happening because they want more money than us.
All those forks have been making bitcoin bleed a lot, but maybe without them, bitcoin would not have the price that it has now.