Actually, there are situations (and it surprised me) when an EG reduction is at least defensible. The winter steelhead EG was originally based on filling up the rearing habitat in the watershed. All accessible areas.
In many PS watersheds, the number of fish spawning in tributaries is falling; trip spawners are disappearing. So, a goal based on seeding the whole watershed is too high if the only spawners you put in are mainstem spawners. Putting more fish in the mainstem doesn't really seed the tribs.
Having said that-and remembering that for decades I supported fixed goals-Karluk Lake sockeye should be an eye-opener. The escapement data goes back about 2200 years. The run has always been "self-sustaining" and probably wasn't fished by humans much until about 1880-1900. The escapement varied from a low of about 400K in 70CE to 2-4M in the 1000-1880 time span. If you make the data set short enough you can just about prove any goal as there are a myriad of ecological and environmental factors that influence survival. Couple that with a pathological need to catch as many fish as possible and we get lower goals.