It does seem like people are slow to adapt, even when it would make sense to do so. Koana’s goal early on was to introduce Sharlayan technology to Tuliyollal after all, and it wasn’t something that was just immediately accepted by everyone with open arms. In the Machinist quests we see people even afraid of technology, as the knights worry about how the introduction of firearms will affect social status as commoners can arm themselves. Outside of the lore, there probably won’t be big changes to the existing areas because this is a game where the differences to each zone over time would only ever be really minor, and combat with swords can’t just stop existing. There’s real life examples of people being slow to adopt new technologies as well.
But I’m personally not finding this game’s introduction of the “sci fi” aesthetic to be strange when considering the context. To me the main offenders are Solution 9 (from a different shard) and anything involving Loporrits (an ancient, advanced, and isolated group) so they make sense. The sci fi aesthetic can show up in other Final Fantasy games. From the ones I’ve played FF8 has Esthar, and Stranger of Paradise has the areas in its third dlc. It makes sense for someone to not like the aesthetic though since it’s so jarring compared to everything else.