This feels like a gross mischaracterization of the intent and work that went into Servo. You say this as if nothing else was being done on Firefox concurrently even though this is demonstrably false - and in fact, portions of Servo were integrated into Firefox (see: Quantum).

Firefox keeps losing on technical merit because it is fundamentally impossible to keep up with Webkit and Blink, which are all backed by massive corporations and are throwing money at the engineering and project resources to actually move things forward.