If it was working as intended there wouldn't be 11 pages of people describing how their parties can destroy monsters at much higher levels.
CR, used as intended, never says you can't beat up higher CR monsters if you get lucky. The 11 pages of stuff you describe is people complaining that their portable power screwdriver isn't good at driving in nails, nothing more.
If the CR isn't doing what it needs to be doing it's meaningless.
That's the real issue; some folks think that CR needs to be doing a thing it isn't intended to do. It isn't CR that is the problem in that scenario, it's just fine for what it actually is when used as what it actually is. It is people expecting that CR "needs to be doing" something entirely different from what it is designed for.
It doesn't make it automatically a meaningful tool if it doesn't even gauge the party level correctly. Let's say you want to need to hammer something into the wall, and then I gave them a banana and say GOODLUCK! The banana isn't meaningless, but in that situation it's clearly the wrong tool for the job.
If CR is meant to be a hammer in this analogy, then the nail would be saying what level at which a party should be able to defeat the monster without much risk of any characters dying. The banana is the unfounded expectation of CR being some laser-accurate gauge of actual difficulty given all the impossible to guess at variables of party composition, circumstantial encounter information, and the skill level of players relative to DM along with a dozen other things like how prone to fudging dice the DM happens to be or how much they manage to play every last monster like a half-stuffed teddy bear.
So you can say how awesome and wonderful the CR is and it does it's job well. Okay, so that might flt into your playstyle. Other GMs may have better prepared characters, those characters might have some sort of crazy item. They may be different level characters. There's literally thousands of character builds using variables such as HP, Skills, Saves, Items, special ablities, magic system etc. If you have had beyond a 9th grade math education you should INSTANTLY see why the CR is godawful at determining this type of stuff. It's like saying
It fits any playstyle that actually uses it correctly, not just mine - literally any playstyle that uses it as the benchmark for when a monster shouldn't be a lethal threat.
Oh, and just so it is clear: I throw out magic items like candy (see any module from the TSR era of the game for example distributions), my players build characters well and play to their strengths as a party well, and I still think CR works just fine - and I even get my players worried they might lose an encounter while staying within the encounter building guidelines of the DMG.
Find X numerically, X is CR and every other letter is a variable that goes into calculating X.
Nope, that's your misconception of what CR represents, not actually what CR is meant to represent.
The GM must understand the game then apply the understanding.
Same goes for D&D... and as a person that has run those systems you mention, and more besides, let me just say that the reason why they don't rely on a CR-like system is more because of their base mechanics than because of some inherent flaw to the idea of gauging what characters should be able to face without anyone dying - as you even note, those of the systems you mention that
can use a system to say "this is okay for your characters"
do, whether it is called power level, tier, or some other name.
And I deleted it because I wasn't originally going to address it, but I've changed my mind: If I can't provide my anecdotal evidence as proof that CR works for everyone that uses it as intended - you can't provide anecdotal evidence from the OP or "hundreds more" as proof that CR as used in 5th edition doesn't work when used as intended.
The fact that you think 5th edition CR is the same as the CR that you call "an awful sacred cow that should have been put down years ago," only highlights that you do not at all understand the intended purpose of 5th edition CR, and are confusing it for 3rd edition CR which is an entirely different beast despite the same name being used for both.
