The major PC manufacturers are also able to provide nationwide or even global service and support, and as you appreciate, they are unlikely to go bust. This usually means they can offer low prices, and ordinary PC consumers tend to buy on price. These industry giants can buy parts in large volumes at low prices, and manufacture their machines on production lines in automated factories. The most popular approach is to buy a standard machine of the sort sold in large volumes by big companies such as Lenovo, HP, Dell, Asus and Acer.
There are different types of PC buyer, and therefore different ways of acquiring a Windows PC. I'm aware, of course, that one drawback is the risk that a small concern may go bust, in which case the warranty will be of little use! The desktop I am considering is the Chillblast Prestige i5 4570I. It claims to use high quality parts in building PCs and seems to offer a good warranty. However, I rather like the idea of buying a product put together by a small company, and have read good things about Chillblast. I was intending to go for another Dell desktop, such as an Inspiron 3000 or the OptiPlex model which you recommended recently. The end of support for Windows XP is prompting me to pension off my old PC, a Dell Dimension 3100.