> what stops them from changing policy tomorrow?
> [...]
> not a benevolent player in the market.
The reason they have this policy today is not because they want to be a benevolent player in the market, but because it has a negligible impact on their business model and it can't be adopted by the competition (Google). I would also argue that that's what prevents them from changing it in the future. It makes perfect sense from a business perspective.