We don't yet know the price of iPhone 9, but it is widely rumored to replace iPhone 8, which begins at $699. iPhone 8 has a single camera and aluminum frame.
Also, 6.1" iPhone isn't dramatically larger than iPhone X.
- 4.7" iPhone measures: 138.4 mm by 67.3 mm by 7.3 mm
- 5.5" iPhone Plus measures: 158.4 mm by 78.1 mm by 7.5 mm
- 5.8" iPhone X measures: 143.6 mm by 70.9 mm by 7.7 mm
- 6.1" iPhone measures: 150.9 mm by 75.7 mm by 8.3 mm
- 6.5" iPhone X Plus measures: 157.5 mm by 77.4 mm by 7.7 mm
So if 6.1" iPhone does indeed start at $699, I think it will sell like a hotcake.