> This isn't the case in every electoral system; for example, in a Parliamentary system such as Canada's, you vote for your local MP, who runs on the basis of a riding, for which there are usually several within a city. The party that wins the most MP seats gets to form a government (PM, etc.) So the election becomes a much more local affair, rather than being a winner-take-all battle among the entire province, and results in practice in a multi-party system.

Parliamentary systems with FPTP also tend toward two-party systems locally, though there is somewhat more variation nationally sometimes. (The US also had some variation nationally, especially before the Missouri Farmer-Labor Party joined the national Democratic Party.)

IF you want multiparty elections locally as well as nationally -- if you want more than two meaningful choices when you go into the ballot box -- you need something better than FPTP as a voting system (IRV with single-seat constituencies is like the smallest and least meaningful step in a positive direction, but STV with multiseat constituencies does better.)