Resource allocation in this context isn’t at all binary.
Given your take, this is a meaningless question, no?
As you point out, all resource usage that lead up to the creation of the diesel engine were necessary preconditions. While one might be able to imagine a parallel universe where the diesel engine was created in another way without all the things in between that might feel like a waste, that is not this universe. In this one, it took what it took.
Same goes for AI. That AI researcher had to eat that sandwich double wrapped in plastic, subsequently placed in another plastic bag in order to get to where he got. Which might feel like a "waste of resources". I am sure you can easily imagine a parallel universe where he didn't eat something that used up so much plastic. But that was the precondition necessary in this universe.
So, ultimately, either everything is a waste of resources or nothing is. And there is no meaning in trying to find a distinction between those two.
The thing is that the steam engine guys researched thermodynamics and developed the mechanics and tooling which allowed the diesel engine to be invented and built.
Also, for every breakthrough like DeepSeek which is highly publicized, there are dozens of fizzled attempts to explore new ideas which mostly go unnoticed. Are these wasted resources, too?