I do agree that the method is sensitive to X-scaling (and also Y-scale, which is logarithmic here!)-- but the "methodology" is at least defensible: scale X/Y to

I do agree that the method is sensitive to X-scaling (and also Y-scale, which is logarithmic here!)-- but the "methodology" is at least defensible: scale X/Y to make existing data appear linear and make the "linear extrapolation in scribble space" meet the deadline at the middle of your X-axis. I'm honestly kinda curious how well this "scribble-forecasting" actually works, but to me this sounds like it could be better than you'd expect from something this silly (but I honestly think that most utility comes from suitably picking between linear, log and semi-log plotspace, allowing you to approximate any linear, polynomial or exponential relationship with a straight scribble...)