Al I can attest to is that 20 years ago they were creating new congregations and today they are consolidating them. In 1999 my wife was moved to a brand new congregation and just a year ago her congregation was eliminated. And to make things worse, these congregations were Hispanic. I am sure things in English congregations are much worse.
It took them over a hundred years to reach their peak. It may take them just as long to reach their bottom. One thing I am confident of, their peak is in the past. Could they recover and reach new heights like the stock market does, I doubt it.