"it's their responsibility to make it fit for purpose"
A laudable goal, but sometimes impractical. I'm astigmatic and need to use a larger font to avoid eyestrain. The 17" screens my workplace supplies can certainly fit this font, but my effective screen real estate is reduced in the process. As I often use multiple windows that need to be cross-referenced, my job becomes harder if I cannot see them all at the same time.
So, I would like to have a larger monitor. However, because the standard monitor is still suitable for purpose, I would have to make a special business case and jump through multiple hoops to get it. This could take months, during which time I'll either get less work done or suffer regular headaches. Or, I could bring in a spare 23" that I had lying around doing nothing at home and use that. Which I am doing, right now. My business case is still processing, but until it gets filled or even if it gets rejected, I'll be able to work properly without hurting myself.