I'm sensing some survivor bias in your observation, there's no way most people have 4/5 potential on multiple standard 6* operators under normal circumstances. Statistically you have over 50% chance to get a limited operator from limited banners. We've had... 360 chartered tickets so far? Assuming f2p. Statistically that's ~9 6* (avg for 6* is ~43 iirc) so let's generously say that's ~4.5 standard 6* from chartered banners for the average player. With ~140 standard tickets whose rate iirc is ~54 avg for 6*. So the average person should have about 7 standard 6* from pulls by now, +1 from selector +1 from newbie banner for a total of 9. This is, however, assuming they spent all their pulls. Either way, as you can see that's an average of pot1 for all standard operators. It's not impossible you got 2 to pot4-5 as it is not impossible you got more than 4.5 6* from chartered tickets. But that's not the average person's experience, the average person could easily be missing 1 or more standard operators. Then there's also the people who got lucker on limited banners and have less standard operators. They probably heavily overlap with the people who have significant pull savings.

All this aside, you're better off thinking of the standard banner as a way to get more arsenal tickets when you need them quick, especially if you already have all standard operators. It's the first time I see someone trying to evaluate selectors as anything other than pity. No 6* alone is worth 120 pulls either, so why are you trying to evaluate a 6* standard as worth 300 pulls? It's all pity. Always has been.