Long time ago I had one particular hardware issue, which Opus 4.6 found a workaround to fix. I don't remember the workaround and being careless (I thought I could ask an LLM again if I needed) I lost that solution. Some time passed and I needed it again - neither one of the newer models is able to come up with a nice solution I had back then. They can solve the issue and find a different workaround eventually, but not as nice. On a side note, I could use 4.6 again of course and try to reproduce it, somehow I only thought about it now writing this comment.
Anyway, my point is that I think these frontier companies are advertising their one-shot model abilities, but underneath the models aren't getting so much better as they try to make you believe.