Making Amtrak LD BC 2x1 would probably attract buyers, but it would cost money to implement and reduce capacity somewhat.
How much money would it cost to simply block one column of seats at booking time? That way you'd end up with 2x1 seating without having to modify or retrofit any of Amtrak's hardware.
All this does is give (potentially, if the whole car is sold) 2/3 of the business class passengers the exact same experience as coach, for a higher price, while 1/3 of the passengers get twice as much space. That just makes the inconsistency worse, which is one of the major problems with Business Class on Amtrak (and has been for years). If anything, you'd have to block 50% of the space to give everybody their own seat pair. Then the question becomes, are passengers willing to pay essentially twice as much for business class vs. coach, because that's what they're taking up.
You could also dynamically auto-adjust available business class seats by rows instead of entire cars based on demand. That way no more than a row or two of buffer space would be "wasted" on business class. This is very similar to how regional length business class is handled on some European airlines. But, it also has the distinction of being very efficient and I don't think that's something Amtrak appreciates.
Since you're in the same car as other coach passengers, you don't get reduced foot traffic / noise, you get the same atmosphere as coach, same seats as coach, and (under current setup), little to nothing extra in terms of service. So...what's the point?