There really isn't much benefit of going above 4K with either TVs or desktop displays and multiple drawbacks. I run dual 4K monitors on my desktop and the pixel size is smaller than you can resolve at reasonable viewing distances, while I've yet to find an OS that deals with HiDPI displays well (Windows and Linux are both terrible at this). If you want to game you are pushing 4X the pixels as with 1080p so you don't get good framerates unless you spend an exorbitant amount on a GPU.
For content viewing, 4K is probably the upper limit of what you want, and if you game there probably isn't much benefit for going above 1440p.
For content viewing, 4K is probably the upper limit of what you want, and if you game there probably isn't much benefit for going above 1440p.