Pre-car every town or city of almost any size was basically a dense core surrounded by farmland-not just in Maine but literally everywhere on earth. There are different subtleties and variations depending on the exact place but that's the basic formula humans have used for 10,000 years. The core is where most of the services and social stuff happened and also where most people lived. To get around you either walked or used a horse, so things were built close together and at a scale meant for humans moving at walking speed. After the industrial revolution town centers were connected by rail so all of a sudden you easily go to the next town or even further, but human-sized design was still the standard.

The current way things are built-spread out and designed for cars, rather than people-is very new, historically speaking; we've only been doing it since about 1950. It's hard for any of us to imagine because we've grown up in it (in the US anyway), but the way things are today is a choice, not an inevitability. The US once had the most extensive rail system in the world and it was literally dismantled to reduce people's choices so they'd have to buy cars, and the auto industry has heavily influenced government policy to incentivize building spread out, car-dependent towns and suburbs, and highways to go between them.

Again, this is the whole US, not just Maine. For example I live in Rockland, and 70 years ago I could have walked downtown and hopped on a streetcar to Thomaston, Warren, Camden, Rockport or Belfast. Now that streetcar line is Rt 1. Personally I'd rather have the train and a grocery store I can walk to.

If you're interested in learning more about this stuff I highly recommend this YouTube channel, and this playlist in particular: https://youtube.com/playlist?list=PLJp5q-R0lZ0_FCUbeVWK6OGLN69ehUTVa