Where can I get a Silent PC?
There aren’t many silent PCs available off-the-shelf for consumers. It is considerably cheaper and easier to build computers with a number of fans, than to build a computer that has no moving parts and is therefor silent. A lot of factors play into this, but one obvious one is just the materials required. A fanless computer requires a large heavy heatsink to absorb and radiate all the heat produced. Large and heavy means more thermal mass, more mass means more raw materials to pay for and process (and metal costs more than the plastic used in fans).
The result is that fanless silent computers are usually hand built by enthusiasts who don’t mind the extra work (and costs) that go into building a beautiful silent PC. It becomes an expression of their identity to show off the unique PC build they produced.