The ranking is dominated by a single commercial constellation, which is the most important fact about the current orbital environment and the one a chart of "space powers" would obscure. Operator counts are not capability: a hundred small communications satellites and one large signals-intelligence platform count the same here.
A ranked bar rather than a treemap, deliberately — a ranked bar is read faster and compares better, and the comparison is the whole point.
Owner codes are CelesTrak's own and do not always map to states: ESA, Intelsat and SES appear as operators in their own right.