Lead time on railcar orders is long. Even if they order new Superliners this year with federal money allocated this year, they aren't getting the first one for at least five years.
The Siemens, Alstom, Kawasaki, and CAF plants are booked several years ahead, and any other manufacturer would probably have to build a new US assembly plant, or at least have to hire new employees. It's going to be Siemens or Alstom anyway.
Also, if it's anything other than Siemens's single-level coaches, design of the new cars is going to take a year or two just to make sure it's compliant with current regulations. Sleepers will definitely take a couple of years of design work.
This soft-surface replacement is designed to keep the Superliners tolerable for that time period, and you can't read anything into it about the replacement of the Superliners, which wouldn't have the first car delivered for years in any case.