That depends on why they think it failed, if failed is even the correct word to use.
I don't think anyone who played FFXI (or didn't play but has done their research) would argue this. It's a factual statement.
The thing that turned people off (and I'd say that's a more accurate portrayal than failure) was that most of these items required luck, massive time investments, or more commonly some combination of the two, in order to obtain them.
Take the events that rewarded long-lasting gear during FFXI's 75-cap era:
Kings (or world HNMs in general): Very long respawn timers with extremely high levels of competition (and frequently botted). Randomly generated loot pools, with the better drops (Defending Ring, for example) being quite rare. Some jobs had very little in the way of usable loot here, especially those added in ToAU and WotG.
Dynamis: Very low drop rates, combined with large loot pools, meaning you could frequently go months without even seeing a specific drop. Competition over zones, since only a single instance of each zone existed.
Sky: Reasonably competitive, particularly against RMT for long stretches of the game's existence. Random loot pools and drop rates, meaning it was possible for the culmination of your work (Kirin) to drop nothing but a wind crystal. Several hour respawns on the pop item NMs. Lots of travel time necessary to get to some of the pop item NMs.
Sea (Jailers): Abysmal drop rates from NMs, with some of the NMs (Jailer of Temperance in particular) being time consuming to even reach.
Limbus: One of the rare events that actually hit loot distribution pretty well, though the boss fight chips limited the frequency with which you could attempt to get the better loot.
Salvage: Even worse drop rates. Frequently possible to do multiple runs in a week and see no drops.
Nyzul Isle: Lots of RNG in terms of what you'd be up against. Smaller loot pools, but most of the drops weren't that good compared to other options.
Einherjar: RNG again. Getting to the Odin fight, where most of the worthwhile drops were, took a minimum of two weeks per attempt, if you had enough mules to quickly farm the feathers from the earlier chambers. If not, it was one attempt per five weeks, assuming you beat every chamber every time. Some jobs had no worthwhile loot here.
ZNMs: Loot was good, but drop rates weren't particularly good, and farming up pop items for higher tiers was extremely time consuming.
I've probably left some events out here, but the general themes should be pretty clear.