Price differences stem from three factors: energy consumption, equipment wear, and operational complexity.
Energy: 2000°C vs. 2800°C power consumption differs by orders of magnitude. Equipment wear: higher temperatures degrade heating elements and insulation faster. Operations: high-temperature processes require more experienced operators and finer atmosphere control.
Vacuum processes additionally incur vacuum pump operating costs and pump oil consumption. So vacuum + high-temperature combinations cost significantly more than atmospheric-pressure processes — this reflects real cost structure, not markup.