Yes I understand that. You are not looking at the whole picture though. I too have cherry shrimp that are nice and happy in a tank that hasn't been filtered, fed or had a water change in at least a month. And has been running this way for almost 2 years I believe. Parameters are fine for now, I too couldn't tell you what they are. But make sure you remember that now is not the future. I know exactly how I set that tank up and how long it should be able to be maintained in this manner. It is almost self sustaining, but IMO such a thing is almost impossible in this hobby. IF you create a tank that is close to self sustaining, it is going to have a "life span" in a sense. Like I said its not magic. Every tank is going to be different. Depends on how much food you add, fish load, and plant growth. Dirt is still dirt, just like enriched/mineralized gravels it can be depleted. This is generally the result of pruning and removal of plant matter. The drain on a tank depends on how it is setup. The soil/substrate is like a big gas tank, but isn't an indefinite fuel source. Most do not run tanks like this because they become depleted and often need to be torn down and have new soil put down. For soil this is alot of work IMO compared to making sure your tank isn't depleting itself. Thats why I only run my little paludarium this way and it will have to eventually be redone, probably this summer with new dirt. If you are ever running a tank this way and notice one type of plant that was happy suddenly stopped or died back thats a good sign you hit a deficiency if nothing else in the tank changed. Especially if most the other types of plants continue to grow.
Also cherry shrimp breed all the time and I can tell you my high tech community tank that get 50% weekly WC breeds shrimp at least 3 times as fast as the one I never touch which is shrimp only.