Time and place sort of thing. There could easily be another timeline where Evangelion and Sailor Moon swap places popularity-wise in the US. The demographic for anime on broadcast television in the late '90s and early 2000s, when Evangelion was getting dubbed, just skewed too young for it to really be profitable in any way. If I remember correctly, it only ever had one complete run on Adult Swim, a late night block which really limited its exposure. I don't think End of Evangelion has ever aired on a major broadcast network. (The Rebuild movies did get play on the revived Toonami about a decade ago, though.)

I don't think Evangelion would ever have been a breakout hit, per se, like DBZ, but depending on the circumstances it definitely could have had moderate success.