Excellent, relevant points and not a complete nonsense argument. Well done.
... also almost exactly the same as providing the first fixed infrastructure link between the 2nd and 3rd largest economies in Europe, for the world's busiest international city to city travel pair, across the world's busiest sea lane.
I can think of a couple of minor differences to the Borders line, but relatively trivial.
Perhaps more clarity is required.
There is a current formula for assessing infrastructure investment business cases, which is highly complex.
The post to which I originally responded listed, in isolation, some population figures and then concluded with the suggestion that those figures, on their own, proved that only one investment was appropriate.
From observing past posts, the author of that post is of course acutely, if not professionally, aware of the complexity of the business case assessment process, and therefore my point is that those with less knowledge might find that particular post worthy of query.
For my part, I have not taken any position on whether I think any extension to the Borders Railway is worthwhile or desirable. Nor have I taken a position on whether I agree with the prevailing business case assessment rationale.
I was merely attempting to use a rather extreme example to, hopefully, light-heartedly address a post on a publicly-accessible and 'Googleable' website which I felt was rather too narrowly-presented.
Clearly, however, there is sensitivity around the subject.