I know this is tech sector funny money and we do just disregard profit and judge companies on revenue alone, but the 5.5 models that just released are quite a bit cheaper than the 5.0 tier.

I wouldn't really be surprised if better model efficiency was part of the reason for a revenue stall, but I would also expect their costs to have dropped a fair bit too (although I have no idea whether that corresponds to an actual cost reduction or if it's all tied up in hardware and land that they already bought and will need to hit more utilisation of now.)