Why did they not conquer inland? Or why did their inland neighbors not conquer them? Argentina, Sweden, and Cambodia have all had great historical highs. Seems like they could have attacked the narrow strip of lands for better control of the sea access
Or if no generalities can be formed, say so!
There are major mountain ranges separating the coastal countries you've cited and the inland countries that may have had conflicts with them. In southeast Asia, the Annamese Cordillera separates Vietnam. In South America, the Andes Range separates Chile. And the Scandinavian Mountains separate Norway and Sweden.
hi! there's lots of room for more info, esp. on Vietnam, but meanwhile you can get started on these for Norway & Chile:
Norway:
Chile:
Croatia / Dalmatia is also a similar example. However, here the conquering Ottomans were stopped when they reached the lower lying land. They easily controlled all of the mountainous terrain of the Dinaric alps for a long time, so they effectively "crossed them".
Unlike the highlands, the coastal area was much more densely populated, and included the old and strong maritime cities and city-states like The Republic of Ragusa, Split, Šibenik, and Zadar (controlled by Venice). They had very strong defenses. They were also quite rich so they could afford defending their surroundings and / or paying tribute to the Ottomans.
That narrow strip of land and the cities there have more value then all of the hinterland combined. For that reason it is strongly defended and not as easy to conquer.
It may be worth pointing out that Norway was part of Denmark for a long time and then in the 19th century it was part of Sweden.
Edit: I swear I typed 19th century, but what posted was 18th.
Trade and fish for the first question! It's the entire reason my province (Newfoundland and Labrador) has anyone on it! It's easier to travel by boat with a lot of stuff than it is over land because water doesn't have as many obstacles (although the few that it does are usually more lethal), combine with a steady source of fish and shellfish from the sea, and you have protein throughout all seasons.
Since the stone age access to food was exceptional at the norwegian coast and transport along the coast was easy. But later it was common to hunt in the montains in the summer. The weekly working time was estimated to 20h. Norway was mostly acoat nation until now.
Source Norges Historie, Aschehoug forlaget