They might have had delivery contracts from before the prices increased, so they didn't have to pass them to customers. Maybe the last servers from those contracts got delivered already and any new orders need to be bought at much higher prices.
Another possibility: They were growing too fast and need to slow down. At some point additional growth might become too risky, or even exponentially more expensive. It might require fundamental organizational changes.
I’m not a business person, but they’re already at the “hundreds of thousands of servers” scale, what about the 41st data center be organizationally far more expensive than the first 40?