Guessing the split here is between internal and external use-cases. Maybe 7% of e.g. Amazon EC2 is ARM, because that's the percentage of orgs AWS and other cloud vendors predict are "ready" for arm. But internally? How much of Amazon S3 is ARM? How much of Cloudflare? Google Search? Netflix? I'd expect pretty high numbers in these vertically-integrated DC niches — they can literally do whatever they want to solve these problems, and one of the largest KPIs for any of these services would be performance + scalability (i.e. requests served per OpEx dollar.)
Why do you think it’s gaining market share? Because more of ARM is deployed than non-ARM.
I couldn’t find the direct source any more, but I remember that in the year 2020 AWS deployed more ARM than non-ARM, and today it is at around 80% ARM and 20% non-ARM for a newly deployed system. You only get to single digit market share because of the enormous amount of non-ARM that still exists and is being used. ARM is growing faster than non-ARM. That’s what I’ve said.