Just my opinion for the sake of being Devil's advocate.
Here are some other variables to consider , the light, flow intensity and a health of the coral itself (mainly does it have the boring algae ) . (And this is just my experience/observation ) .
Are the corals in the tank healthy to begin with?
Do they get enough light ?
Is the flow adequate ?
Basically are the other parameters on point, are there any swings?
I like to compare the high levels of phosphates to ick in a way. If your fish is healthy and not stressed out by any other factors while you have ick in the system, they will shrug it off with no problem.
Now if one day you start stressing the same fish to the point where you start seeing bunch of dots on them, then ick really becomes a problem and further hinders the recovery of the stressed fish. If the system does not have ick and the same fish is stressed out in a similar manner, after you remove the stressor it will eventually recover to its normal state.
Similarly , if someone keeps acros, that are super healthy, and receive enough light, super solid parameters, large water volume enough food, having high phosphates probably won't affect them . Now in reality most tanks are smaller and sometimes we get a calcium swing or alkalinity or salinity or we tinker with the light , or the light is too low , bam there are phosphates causing acros to brown out , stunt growth, fueling the boring algae, you name it. System with lower phosphates .03-.04 on the other hand is somewhat more forgiving since a stressed coral doesnt have phosphates to further limit its calcification/growth and the recovery process.
My system is lower light and believe me getting my phosphates above .1 stunts all the growth , 0 PE, STN, you name it . After adding gfo everything comes back to normal, visible daily growth, no STN.
I know of a reef tank (LFS tank) that has .22 phosphates with great success, the tank is also infested with flatworms and red bugs. I think that the tank is 400 gal and around 25 years old, the tank is old school so it has 6 MH and 6 t8 bulbs . If I'm not wrong I think they told me that it's about 1000 par at the surface (I might be wrong) . Their colonies grow like crazy and look amazing too, one problem though a lot of their acroporas have boring algae in them. They seem to outcompete it with no problem in their tank, here's a problem though not everyone has MH T5s or even (radions*) to provide the corals with ton of light. Some people have mixed reefs and higher light tends to bleach lps and shrooms so that becomes a limiting factor also. Moreover, if you have LEDs often one side of the acro gets the light and the shaded side just Browns out or loses the color. When you move a coral from an old school tank like that into a tank with lower light and high phosphates acros don't tend to grow as fast but the boring algae doesn't care and eventually outcompetes the coral.
So finally
I think there is more than just 1 variable,
Just like the higher alkalinity causes the problem in a low nutrient systems . I wonder if there is a similar relationship between the light intensity and phosphates or the flow and the calcification rate. Etc .
PS: don't mind my terrible grammar it's 4:30 am no time to fix it .