It works pretty well for me to just include <name of town> in my search query if I want local results.

That fails without personalization. Take the example of Dublin. My IP is in Europe, but DDG returns a bunch of results about Dublin, Ohio when I look for "Dublin McDonald's" before eventually linking McDonald's Ireland. Imagine how bad it'd be in Dublin or Pittsburgh, CA or worse, large cities that share a name like San Jose or Ontario.

Try "Dublin ie McDonald's".

That still doesn't resolve the ambiguity of Ontario, which is in both California (CA) and Canada (CA). Moreover, the search is getting a bit unwieldy.

The point wasn't to illustrate that there's no way to produce the information without personalization, it's to illustrate that search queries can become much more relevant and straightforward with it in particular, common scenarios.

>That still doesn't resolve the ambiguity of Ontario, which is in both California (CA) and Canada (CA). Moreover, the search is getting a bit unwieldy

"ON" or "CAN." And adding 2-4 letters is hardly unwieldy.