The assumption of predatory pricing is that it's not easy for a competitor to just show up. Supply chains would be destroyed, capital equipment scrapped, etc and replacing them would be time consuming and expensive.
Sometimes that's a reasonable assumption to make, sometimes it's not. Even if the assumptions are unreasonable, many CEOs won't let mere reason stand in their way.
> Maybe raise them to at-cost, but if your Widgets can comfortably cover the cost, then there is no reason to raise prices.
So, the Widget-making capital would just sit there producing 0 ROI? Someone's gonna object to that. A company pursues market dominance to make money.
Nobody can compete with you on the price and it is clear you can unbundle your Widgets from your Sprockets at any time if you ever feel threatened.
Why would you raise prices after? That would just invite competition again. Keep the prices low and competitors away. Maybe raise them to at-cost, but if your Widgets can comfortably cover the cost, then there is no reason to raise prices.