That was a very interesting read and video!

I would like to point out something though: earthworms in N. America are introduced. There were worms once upon a time in N. America, but they (mostly) disappeared long before colonization.

When colonization started, earthworms were introduced from the soil used as ship ballast and afterwards from agricultural and horticultural products amongst others.

So the part they play in the places of N. America they have colonized is a lot more about disturbing the soil ecosystem than playing a vital part on it.