This is exactly the issue and I have also seen it at the workplace. There are people who find task X as a go/no-go. If it’s no-go, the issue is closed. So you say, “what about option B?” Option B is also a no-go. Issue closed. You have to ask them to propose an alternative in case the task can’t be completed as directed.
When I’m a supervisor, I consider it my job to tell people what the parameters are for the task. “Look here, but if it’s not there, try anything you can think of” or “Get X. See what you can find going in cold. If you have trouble getting started, come back and we’ll brainstorm.” Etc.
I’m a buyer who has to deal with weird offbeat purchases, yet conform to state and federal government rules of fair competition and fiscal accountancy. I think I get what you’re saying. And like others said, it’s not so much that she’s taking no for an answer, she’s not thinking of the alternatives.
My suggestion would be to take the next situation when something like that comes up and go through the alternatives before she starts looking. Ok, you need to find 40 3 ring 1” binders with pockets in blue. The variables here are the quantity, number of rings, thickness, pockets, and color. Probably the rings are not an area of compromise. Quantity is probably a minimum (you may have to get them in lots of 10 or 12) so they may have to get 36 or 48. Thickness is probably a minimum; they can probably go for 1.5”. Pockets are probably not negotiable. Color? See what they DO have.
Phrases you need to use with vendors: “what HAVE you got?”, “is there a x-ref?”, and “give me some ideas”.
If you are talking about this sort of initiative to never go to your end user without some sort of answer, it most definitely is not age related. We had a woman in her forties who simply could not figure out what to do when she hit a wall. About the fifth time I asked her if she’d googled the part number, I was ready to brick her cubicle shut. Our youngest hire is the quickest to pick up all the techniques.