Who is doing Eureka though? New players, or those returning after months or even year long absences. Meanwhile, the players complaining are those who don't want to take six month long breaks just to have something to do. Case in point, I'll be tackling Bozja the moment it releases. I'll have long finished it before 6.0. The content released per patch should be able to sustain nearly the length of said patch with some reasonability. Obviously, the dev team isn't going to cater towards players who spent 6-10 hours a day playing. But when you can finish nearly everything in a week. Longevity is a problem.
As for Ocean Fishing. Your methodology is flawed. Content with less staying power should be less prioritized because it won't engage the player long enough. Since people typically like building multiple relics, it makes far more sense to release grindy options like that early so their life cycle stretches beyond the current patch. Imagine if Bozja released in 5.1 instead of Blue Mage and/or Ocean Fishing. We'd all have something to keep us occupied right now.
Naturally, but for many people those are simply "chores" or things that simply don't last. I enjoyed Copied Factory but there's only so many times I care to run the same easy raid before I'm just bored. Dungeons are even worse. I never touch 50/60/70. Why? Because the rewards are awful and I've ran every dungeon hundreds of times. It just isn't that fun spamming the same 1-2 AoE combo. And oh boy is it boring, especially as a healer, if a tank small pulls. You literally don't heal. I, too, play other games. I shouldn't feel like I need to play several other games because XIV just doesn't have enough to keep me occupied.
