Because many companies are run with a mix of cost and profit centers. If you run IT as a cost-center and allow bean-counters to “optimize” things, you can easily get outcomes like that.
Making a computer faster for a worker who isn’t on the critical path and who is almost never waiting on their computer doesn’t make sense. Most of accounting falls into one or both of those tests, so they could rightly decide to optimize for cost. They can then wrongly conclude that they’ve already solved that question universally and apply that solution to devs.
Even a lot of IT employees don’t care or don’t know. Some want to just order something that users won’t revolt over and make the deployment and warranty support a first consideration.
Having a fast NVMe disk, 16/32 GB of ram and a current generation (or previous generation) CPU should be the standard for a developer.
Apart from that there is the crappy office keyboard, mouse and all too small mousepad. Fortunately those things can be replaced without much issue.