Well now Threads just reached 100 Million users. It took only 5 days for this very big number to pass. And still it is not available in Europe. 

This is compared to ChatGPT that took 2 months for 100 Million users. https://www.dailymail.co.uk/sciencetech/article-12282593/Metas-Twitter-killer-app-Threads-passes-100million-users-five-days.html