Admittedly, I didn't click your link, however, based on what you've stated, there is some inaccuracy. All these big companies take your requests and the context, and route it based on the content, cost, etc.

What Anthropic presents as Opus 5.5 isn't actually a single model...it's Anthropic's ecosystem as a whole. If you are lucky, you get the top model handling your issues all the time, however, that never happens. What really happens is that your request and content are graded along with your subscription (example: API? subscription, if so, what tier? how much has the user used it? Do we trust the user? how much? how much are they paying? are they asking something we think is dangerous?) and your request and context are routed accordingly.

Anthropic isn't alone in this behavior, Open AI does it as well, just look at the respective subreddits on reddit for both if you need some examples, or just play around with the various models from both companies.

There are a few folks who've done some analysis on this (their findings were posted on reddit and X), and a bigger multi-national study is apparently coming, though I admittedly don't know their findings.

I guess the tl;dr is that Anthropic and Open AI are actually selling you "best-effort" routers, so you may or may not get the best in class model, and only they get to determine if you do or do not. No guarantees.