It's perfectly fair to say that constructing a road to a remote community will mean better ... everything ... for that community, but you're blaming them for not also building a hospital and a school at the same time as the road.
I mean, yeah, technically it's possible that we lose current capacity and we never get enough space capacity to make up for it but if you argue for this particular outcome, I think it's rather improbable. The parent made a very good point: cheaper and better lift to orbit means better ... everything. It would mean you have cost and capacity improvements for the whole chain, and yet nobody bothers to use this for JWST successors. That's a very thin line of probability you'd be arguing for.
And no, the condition doesn’t need to be that nobody bothers to use it, it’s that it doesn’t get used at such a scale on a timeframe people care about to replace the infrastructure it destroyed.
It’s actually super straightforward.
The response seems “opposite” what was said because if you read between the lines, the whole comment was about hypothetical future improvements to the cost dynamics.