I stole this from another thread , this poster posted what I’ve always thought
When the bar was lowered for gala night dress requirements — possibly in response to post-cruise surveys and complaints from those who couldn’t enter the MDR without proper attire — the catalyst for cause and effect was initiated. If you can’t be bothered to dress special, we can’t be bothered to serve special. Personally, I prefer that the F&B budget be spent on quality beef and lamb — because I am not a lobster person — but if the passenger is going to insist on lowering standards then the cruise line will oblige.