Sure, there was a time before 4X was a term when games that would now get that label would not have a narrower subgenre label than “strategy”, that doesn't mean that what strategy meant then was what 4X means now, it means that there weren't enough 4X games to distinguish them within strategy (nor enough turn-based strategy and overlapping label to 4X -- but not all TBS are 4X, and there have been realtime 4X games -- to segregate those out.)

RTS wasn't coined to distinguish StarCraft, etc., from “strategy” which label later evolved into 4X, it was to distinguish it within “strategy” from TBS, which also didn't need a label until RTS was common enough to distinguish the two.

Plenty of strategy games prior to Civilization that weren't 4X or 3X, Fire Emblem, North and South, Nobunaga's Ambition, etc.