In RTS terms this seems more like 'supply' or 'pop' count: a measure (often ingame) of the relative power (and cost) of each unit, such that equal supply counts

In RTS terms this seems more like 'supply' or 'pop' count: a measure (often ingame) of the relative power (and cost) of each unit, such that equal supply counts of different units are in theory on the same footing (often with a hard cap to avoid game-breakingly large armies), absent any specific advantages or counters. Even small differences in supply can be extremely significant in most RTS: a 2x supply advantage is almost always overwhelming. Hard counters are exactly what would be a counterexample to that.