Finally, while I've no doubt that a Silver running to/from Boston would help revenue, I seriously doubt that it would increase it by a factor of 10.
I don't see how it would be possible to increase revenue by a factor of 10 ... or even much at all. Aren't the Silvers running pretty much full from WAS south already? That means there's no capacity to add passengers except between BOS and WAS, and given that the train probably starts out at half-full in NYP, most of the new passengers from BOS wouldn't even be able to travel all the way to WAS.
I'm not saying nobody from BOS will ever be able to get to MIA; I'm saying that for every passenger originating in BOS who books to south of WAS, Amtrak is probably just getting revenue they already had from a passenger originating somewhere NYP-WAS who now cannot ride the train. There's no net gain here for Amtrak, except that they're selling fares from BOS-NYP ... but are they even gaining ridership there, or would it just draw ridership off of regionals and Acelas which are already not typically full (in my experience) on the BOS-NYP run? I'm not even convinced they'd gain much revenue from BOS-NYP -- certainly not over and above operating costs. Given how empty the sleepers would run BOS-NYP (because so many bookings will be for passengers originating NYP-WAS) I suspect the sleepers would run at significant loss for that segment.
There's little extra revenue for Amtrak to pick up here, unless they're able to significantly lengthen the consist in addition to possibly needing an entire extra trainset given the extra length of the run and scheduling necessities.
Or unless they run a separate section (coaches, cafe, and Viewliner, and maybe a baggage) BOS-NYP which couples onto the full train at NYP. But then you're talking about a switching move. It might be the best approach, but it's still a lot of extra resources, time, and operating costs compared to ... well, I'm not sure how much gain you'd get. Some, but surely not tenfold!