I think this is a great question. I’m going to take a stab at it. I’m also going to talk about it in the US, as I’m less familiar with other English speaking countries’ town names and am not at all familiar with the way other cultures name their towns.

First, a lot of US place names come from local indigenous culture. Indigenous languages have a lot of variability. I’m pretty sure every state has them, and the names will vary based on the local languages. Many of the state names have similar origins as well.

Second, many towns were named after people - either for the founders or for a notable person. The US Census Bureau estimates there’s about 150,000 common last names in the US, and only about 5100 common first names. Because towns named after people tend to use their family name (although it might be cool to live in a town named Steve), they’re drawing from a much larger pool than the first names.

Third, and related to that, last names stick around longer. First names go through fashions. Every generation has its own trendy names, which further reduces variability for the population at any given time. There aren’t a lot of girls getting named Elenor or Eunice these days, I’d suspect. We tend to mostly know people around our own age, give or take a decade or so, and therefore the number of first names you tend to encounter in your social circles will be small. Couple that with the fact that people living in culturally homogenous areas are very unlikely to run into a lot of foreign first names. I think your chances of being friends with a Puneet or a Rupak are fairly small if you’re from a small midwestern town, versus James or Scott.

So, basically, I hypothesize that it’s because they’re sourced and sampled differently.