That's not _entirely_ true. Search Console now has a Generative AI page where you can see impressions per page now. Bing has something similar.

Also, I would assume that really "GEO" is just like "SEO". If you rank on the '1st page' of results for whatever common searches, you are _very_ likely to rank the same way for LLM questions, because all the LLM is doing (nearly all of the time for 'best roofers in Houston') is doing a web search and summarising the first x results. So if you are on page 1 for that term, it's very likely IME that you will get mentioned on LLM answers for that.