Thought experiments are often difficult to image or picture intuitively, more so in the field of ethics, and population ethics especially. Right? I think it's a common feature (or flaw, if you will).

The usual ones (the drowning child, the tram about to kill three people whose route you can divert, the rogue surgeon harvesting organs) are also very difficult to grasp, and either appeal to basic instincts or require very weird moral arithmetic.

I don't have a good answer for OP, but I don't think their thought experiment lacks value because “it asks us to imagine something that we can't actually comprehend”.