They exist because they are either proxying networks that resell residential IPs (aka your internet connection) ...or because they are harvesting credentials.
The former will now make less sense as a business model, since UK isn't a good location to proxy traffic through anymore.
If your company built a super intelligent LLM, say that could find Alpha in the financial markets, would you make it public to anyone with a ChatGPT subscription?
Of course not! They would use it to trade and would keep it concealed while throwing the public a bone with a less advanced version. Same thing applies as AGI or even as code gen gets better.
How likely is it that you saw a plane made by humans that you misclassified due to lack of data vs how likely is it that it was actually an Alien made aircraft, coincidentally working in our atmospheric conditions, gravity and drag related physics?
Guess what, it's about likeliness and you are extrapolating the wrong assumptions. Extraordinary claims require extraordinary evidence, not the other way around.