To be fair, it can be quite a difficult premise since it involves writers to actually think outside the box and focus on world-building or character driving, instead of relying on tropes like the ones you mentioned. So probably that's why it isn't as widely used, and when it is, we get very interesting stories like this one. Honestly Frieren was not only a breath of fresh air that was sorely needed, but also revolutionary in both premise, storytelling, etc. that writers should definitely learn from.