I agree fiction is a bad argument.

On the other hand, firstly every single person disagrees what the phrase AGI means, varying from "we've had it for years already" to "the ability to do provably impossible things like solve the halting problem"; and secondly we have a very bad track record for knowing how long it will take to invent anything in the field of AI with both positive and negative failures, for example constantly thinking that self driving cars are just around the corner vs. people saying an AI that could play Go well was "decades" away a mere few months before it beat the world champion.