I've run the same soil for I don't know how many grows. My plant growth kept getting worse a little every grow. It was slower and the yield was lessening. At first, I couldn't figure out why it was happening. Eventually, after doing lots of web searching and reading about the symptoms, I decided the pH was too low. I added dolomite lime, and the plants responded well.
So, the question then was, why was the pH so low? I found two likely causes. One was repeated use of Epsom salt. The sulfate makes it a mild acidifier. It doesn't have an immediate effect, but it can decrease the pH over multiple crop cycles. A second cause is decomposing organic matter. The pH of compost is neutral, but the decomposition process produces acids. Those, and perhaps other sources of acids I haven't identified made my soil too acidic.
So, my soil was increasingly acidic. I didn't have a pH meter at first, but after 8 tablespoons of dolomite lime in 5-gallon pots, the pH was 6.4. So, I think it's a fair assumption that the pH must have been much lower before adding the lime. I finally got the pH close to 7.0 in all pots except one. I'll add more lime to that one at the next watering.
This soil was mostly FFHF with some FFOF. Both have plenty of organic matter. I also had amended other organics. I'm sure the pH of those soils is okay out of the bag. Repeated use must have had a cumulative effect.
I'll look for that. I haven't been following that thread because I can't keep up with it. It's huge and there's a lot of noise. Have you thought about making a new 'trainwreck' thread every year?
I don't think I've seen that brand. Anyway, after several years of use and various amendments I doubt the beginning brand matters. Eventually any soil will be depleted if it's not replenished. The challenge is how to keep soil fertile.