As far as volume, they peaked 4 years ago. Not 40. They will be fine, as always.
I wanted to respond to just this... you keep mentioning their history as if it can predict the future.
The last time they lost their mail volume because of the internet........
Oh wait, they are in territory they have never been. All of those cost cutting measures were in 2008. They shaved $6 Billion in costs. They cut all those man hours that amounted to 60k+ full time jobs... and they still lost $3 Billion (on top of the $3 billion the federal government gave them... which means they really lost $6 Billion. And if you count the Billion they had in the bank at the beginning of the year... They lost a whopping $7 Billion the year that they had all the cost cutting measures.
Now we are 2.5 years down the road, and those cost cutting measures didn't even slow down their losses. Their whole business model is failing.
I can't find any numbers to support it anywhere, but I can almost guarantee you that they haven't had mail volume fall off like this EVER, and they know it's NEVER coming back.