Not everything from the same eras have to necessarily be discovered within the same time frame in our world, as compared to the real world. Some aspects could exist while others not so much.

I think we should avoid trying to make our Minecraft world analogous to the real world in terms of eras or technology, and focus instead on creating the world feel we want. I'm concerned that if we define this too stringently, we will ultimately limit how creative we can be. I think that what counts as lore-breaking and lore-compliant will evolve organically along with the community.

More broadly, I think that gameplay should inform lore, instead of lore informing gameplay.

We also don't need people building steamboats and artillery as well, so we do need some kind of frame of reference.

Not being stuck in one period is something I don't think anyone disagrees on.

True. Perhaps this is a case of dealing with things as they come up instead of setting strict boundaries perhaps? In the past, when a build hasn't jiived with the community's lore idea of the world, it has been dealt with effectively (aka the giant duck ). How can we put definite limits on things that are maybe not even thought up yet?