Demos are incredibly risky for both consumers and developers and offering them should absolutely not be a universal principle.
How can it be bad for a consumer?
- Developers can jam in the best bits of the game into a demo like how the best jokes in shitty comedy movies all appear in the trailers. When you get the main game and realize you've already seen all it has to offer, you'll be disappointed.
- Developers can set unrealistic expectations for the game by offering better graphical fidelity and stability in a demo that doesn't not actually represent the finished product.
How can it be bad for a developer?
- Some games are too complex and/or nuanced to represent in a 30-60 minute demo. Bravely Default is a good example of a crappy demo that didn't represent the finished product.
- It can also end up being a waste of resources to develop a demo that few people will actually download and play.
Overall I think demos are good, but in some cases they can be very bad.
How can it be bad for a consumer?
- Developers can jam in the best bits of the game into a demo like how the best jokes in shitty comedy movies all appear in the trailers. When you get the main game and realize you've already seen all it has to offer, you'll be disappointed.
- Developers can set unrealistic expectations for the game by offering better graphical fidelity and stability in a demo that doesn't not actually represent the finished product.
How can it be bad for a developer?
- Some games are too complex and/or nuanced to represent in a 30-60 minute demo. Bravely Default is a good example of a crappy demo that didn't represent the finished product.
- It can also end up being a waste of resources to develop a demo that few people will actually download and play.
Overall I think demos are good, but in some cases they can be very bad.