Sometimes the entanglement happens because Y is the entire elevator pitch for the whole thing.

Get rid of Y, and you're left with "I used Z as intended and it solved the problem with some minor annoyances" or "Yeah, I just shaved it down a bit to fit and used epoxy, no need to CNC an adapter".

Especially when X isn't the actual problem. Sometimes the actual problem is "I've become obsessed with stuffing Y into something".

Another aspect of this: more often than not Y is a solution that has side benefits that are not explicited in the request.

The obvious ones are buying a new computer to use a resource intensive software. There might be options to upgrade the existing parts to cleanly meet the requirements, borrow/rent a machine for the length of the project, spin up a machine in a cloud, straight ask someone else with an adequate machine to inherint the task etc.

Those could all be more optimal solutions, but I'd still totally ask for a new computer instead.

In my case it's very often the opposite: I have already thoroughly examined potential solutions Z, W, V, and Q, and have found them to be unworkable, decided that Y is the path forward, but am not sure how to implement it.

And then I have to spend two hours explaining X, and then patiently explaining why Z, W, V, and Q don't work before my colleagues finally agree with me that Y is what we need to do. Sure, very very occasionally do they come up with alternative T or perhaps K, that I hadn't considered, but I usually find that Y is still the way to go, or at least workable solution of similar complexity.