A few corrections are in order.
1. The S-97 Raider will NOT be the demonstrator for JMR-TD. The SB-1 Defiant demonstrator will be a full-scale 30,000 lb class machine. Sikorsky/Boeing is very confident the configuration will scale up to this size. But that is near the size limit for this configuration. Significantly larger rotorcraft will require a different configuration, either single rotor, tandem rotor or tilt rotor.
2. Sikorsky/Boeing and their partners have ALREADY spent $250M of their own funds, and plan to spend roughly 4x what the government will provide to develop and build the SB-1 demonstrator.
3. CG envelope for just about any aircraft is quite limited at max payload. However, CG envelope for lighter payloads is much larger on an inline tandem rotor than either a single rotor or side by side tandem like a tilt rotor. Since 90% or more of missions are performed at well below max payload, that is a significant advantage operationally.
4. Sikorsky/Boeing perceives they have an advantage over Bell/Lockheed's tilt rotor based simply on the fact that this is an Army program. The US Army is not keen on tilt rotors and has bought not a single V-22. Bell has some serious selling to do to overcome this Army bias. However, similar conventional wisdom in the 90s was that USAF would never buy a turboprop to fill their JPATS requirement. Beechcraft proved them wrong. We'll have to wait and see if the alleged Army bias against tilt rotors is true.