Like minds. I have been saying the exact same thing for years to any that would listen!
The new stat guys bring up other advanced stats that try to do that, but it never really does. I also think that the number of outs should be factored in. And number of bases occupied. That is where it would get more tricky, with the other two factors invloved. But am am so over reading how well a reliever does, without factoring in that he did not provide relief, and let one to three runs score with two outs for example (even with the bases loaded), and all they needed to do is get a ground ball, fly out, pop out, or strikeout, the outcomes of an AB that happens around 68% of the time, anyway! (Considering that MLB average OBP is currently .323 for 2023)
I don't really care about the why. That is way too subjective. And I don't consider ERA useless at all, even though flawed. But it could be tweaked, and the %s proposed are still not confusing, like some other advanced pitching stats.
The relievers come in and give up a first pitch meatball, throw a wild pitch..... and they ruin their teammates line that just pitched 7 innings, and didn't want to come out, probably would have been fine to finish the inning - they just struck someone out, then gave up a walk that was a bad call by the plate ump, and then a dribbler that the third baseman couldn't make the play on, gets pulled with runners on second and third with one out, and the reliever comes in and gives up a wild pitch, and a single, and then strikes 2 out, and the starter gets the runs and the loss perhaps, and it looks like the reliever did great in the box and for his stat line..... all except the most improtant relief stat..... that shows they provided relief.... Inherited Runs Scored.