This all comes down to how you interpret the 10,000-step rule/suggestion. Your interpretation, as “more than 10,000 steps is better than fewer than 10,000 steps” is not, I believe, how most people would understand it. Because for any “normal” number of steps, more would always be better than fewer, according to our current and common understanding of the benefits of physical activity. This would lack any explanation of why 10,000 is being suggested, when the same is just as true for 1,000, or 5,000, or 12,765.
There is the interpretation of the 10,000-step idea where it’s the necessary minimum for benefits. Or, weaker, some sort of prominent inflection point on the cost/benefit curve. I believe this is closer to how it is generally understood. The study obviously disproves the minimum idea, and arguably also shows that most of the benefits are achieved long before reaching 10,000.
As an aside: This study doesn’t support, or at least it doesn’t prove that more than 10,000 is better than less than 10,000.
We do know that, beyond some point, physical activity stops being beneficial and becomes harmful. Olympic medalists, for example, tend to die earlier than both non-medaling competitors, and the general population they are from.