If you're optimizing purely for maximum ROI, then that's the correct product decision. Whoever achieves maximum ROI attracts the most additional capital invest

If you're optimizing purely for maximum ROI, then that's the correct product decision. Whoever achieves maximum ROI attracts the most additional capital investment, which enables them to lower unit costs and continue improving that ROI further, thereby gaining even more capital, etc. EDIT (since I'm getting downvotes): to be clear, I'm not advocating this particular "maximize overall ROI" decision as a moral good. I'm just pointing out that, empirically, this is what the market is actually optimizing for, irrespective of my feelings about it. That's the reason why they do it; it's not because they're dumb.