This analysis by @boilingsteam is the most reliable estimation of #Linux distributions usage I know of.

Until 2012ish MediaWiki published statistics based on browsers' user agent.

At the beginning of this chart there's a similar scenario 7 years later, with Ubuntu very strong, but in 5 years the picture has completely changed.

Arch has dethroned Ubuntu (among gamers at least), the ecosystem is more diverse, and new distros gain terrain.

Eagerly expecting updates!

https://boilingsteam.com/ubuntu-and-manjaro-fall-further-into-oblivion-february-2024/