Well, this neglects the treaties signed in Ghent or Paris or London or the treaties of Rome. But I see your point, in many cases it was a matter of convenience. Take Guadalupe Hidalgo for example, President Polk sent Nicholas Trist, the former US Consul in Havana, to negotiate with the Mexican delegation in September 1847 after the fall of Mexico City, and the Mexican government had relocated to Guadalupe Hidalgo in order to escape the advance of the US Army. Trist actually was recalled by Polk, because the President wanted to hold the talks in Washington DC. Trist however disobeyed Polk and went ahead with the talks where he could, basically took the terms to the government, where they happened to be in Guadalupe Hidalgo. He did so, thinking rightly or wrongly, because he felt that the negotiation positions of both parties were unstable enough that any delay might result in a regression towards hostilities. He made a judgment call on that basis, the geographical location was I suppose a secondary or tertiary consideration. When one considers that Mexico gave up over half of its territory under the terms, this is the type of peace settlement that can’t be passed up, big city or small town asides.

In the case of Versailles in 1919, the actual peace conference had taken place at the French foreign ministry in central Paris: the hall of mirrors at Louis XIV's palace was chosen as the venue for the signing of the treaty with Germany because it was there that the German empire had been proclaimed in 1871, and it was also at Versailles (the German headquarters during the siege of Paris) that France's government was made to sign the subsequent humiliating preliminary treaty after its defeat in the war of 1870; the symbolism had also been reflected in the conference's opening on the 48th anniversary of the first event.

The treaties with Germany's former allies were similarly signed at western Parisian suburban locations: St-Germain-en-Laye (Austria), Neuilly-sur-Seine (Bulgaria), the Trianon (specifically Louis's Grand Trianon château in Versailles; Hungary), and Sèvres (Turkey), though the last never bacame effective and was replaced by the 1923 Treaty of Lausanne. The 1919-20 treaties were nevertheless collectively called the Paris Peace Treaties, though the term "Versailles settlement" later came to represent the postwar status quo.

The precedent of scattered signing venues wasn't repeated in 1946 when the treaties with Germany's European allies were negotiated at the Palais du Luxembourg in central Paris and signed the following February at the foreign office. (Though the formal state of war had been ended in 1951-55, the final settlement with the two German republics was signed by the former occupting powers in Moscow in 1990 shortly before reunification.)

Brest-Litovsk was the German headquarters in the 1917-18 campaigns against Russia, so it was there that the Soviet negotiators were summoned for the armistice and subsequent peace talks - hence it's analogous to Versailles in 1871.

So sometimes there's symbolism, sometimes it's at the victor's convenience (or occasionally at a defeated adversary's seat, e.g. Gadalupe Hidalgo) and sometimes (e.g. Lausanne) a neutral venue is chosen. And our common naming conventions aren't uniform: the 1925 Locarno treaties were actually signed in London and so named at the time, but they're generally remembered by the place where they'd been negotiated.