Is it really though? I'll hold my hands up and admit I've had a few wipes here and there on large trash pulls, some were my fault, some were someone elses. However, the only time I've ever wiped to a roulette Dungeon Boss outside of Pharos Sirius and Amdapor Keep circa 2.0-2.1 would be on Baelsar's Wall, usually due to the rest of the group ignoring the collar on me (My only post in the bad duty finder experiences here was of a monk ignoring nails+collar, then blaming me for us wiping when I was dead 'because I wasn't healing' for example).
Probably my most defining memory of how trivial most dungeon bosses are would be in Gubal HM, I DC'd fairly late on Strix, came back right as the group wiped due to no heals and proceeded to solo the last 20% or so myself.
Compared to the horrifying trains, wall agro and nightmare corpse recoveries I saw in MMOs of old such as Everquest and FFXI or even WoW in it's 'everything has to be CC'd or your tank goes splat phase'. Then yes, FFXIV's dungeons are a comparative cake walk. It wasn't always that way, Brayflox and Tam-tara in beta/prerelease and Amdapor Keep in early 2.0 plus pre nerf Pharos Sirius were actually pretty challenging. It's very well documented that SE lost their nerve over the backlash regarding Pharos Sirius.
Have you done much O3S yet? That's a pretty significant step up from O1S-O2S and I suspect it might be a bit of an eye opener for you assuming you didn't raid in ARR/HW.