I think in this particular scenario it's shortsightedness. They see this an instant increase in revenue without considering that longer term this will destroy their ever dwindling market share.
Many C*Os plunder the companies they work for, then move to another one. They don't care about the market share of the company they'll leave, no more than bugs care about a tree they are eating. They'll move to the next one. There is always a next tree, until suddenly there are no more trees nearby.
Because no one rewards long-term efforts. You are rewarded for short-term goals and, at best, mid-term ones. In an abstract sense, customers reward you for long-term efforts, but this is something no one will put in an Excel spreadsheet with financial voodoo calculations, except when you are the sole owner of the business.
Could this perverse incentive be rectified in some way? Perhaps by offering much of the compensation in equity that they'd have to hold on to for decades?