This is not proof this is speculation by specialists instead of data that we can verify. They have made a fancy graph without backing up their claims and providing the article that you gave has not solidified the claims any more than the OP was claiming. I want to see actual data and how they conducted the survey to get these results.
The article has a link to the original source of the study:
The 25 Countries Most Prepared For A Cryptocurrency Takeover.
At the end of the study you can check their "Methodology". That is all I could find and since one of the items of the study is "predicted 2025 search volume", you are right by pointing out it has a speculative characteristic.
I am not claiming that the US is not leading the race but I have my doubts in the survey that is in chart form here because I would expect other major countries to be higher on the list. The USA being a large country is going to be one of the highest and because the US does not have the problems that the middle east have they will have better access to the internet etc and they will always be high on the list but I would expect China to be higher before the bans that were announced.
I think China couldn't be on this list because officially they have always been very hostile towards bitcoin besides being a very closed, restrictive country. It wouldn't make sense if they were leading global adoption. Moreover, chinese citizens have to use VPN to access the internet and deal with crypto currencies, so it would be really hard for the study to collect legit crypto uptake and crypto search volume data from users living on that country.