Have any Spartan deaths actually happened due to a lack of skills on the Spartan's part, or are most due to unfortunate circumstances?

Nearly every dead Spartan I've both read and seen in both the games and extended lore has died not because of their own lack of skill, but overwhelming forces or just bad luck.

The Headhunters in Halo Evolutions, Roland and Jonah, both died fighting what was considered the Covenant's top assassins and still took out, what, like a dozen of them? Even after Roland gets killed and Jonah loses an eye to the Silent Shadow elites, he still manages to detonate his explosive charges and kill all but one of the Silent Shadow members.

Four Spartans die on the way into Reach in Halo: First Strike when Covenant anti-air hits their Pelican, and several more die on Reach defending against impossible odds.

Black Team, ignoring the stupid way in which they die, are killed by a millennia-old superwarrior who was the chief warrior for the Forerunners until his imprisonment.

Noble Team all die not due to a lack of skill, but because in one way or another, something went haywire, or somebody got the drop on one of the team, leading to their deaths. Jorge, cause the jerry-rigged Slipspace drive malfunctioned, Cat because her shields didn't work properly, Carter from some kind of Banshee ambush, Emile from an Elite Zealot stealth killing him, and Noble-six dying after killing a small army, then fighting to his last breath even after 3 Elites rush him.

Cal from Halo Evolutions also dying because, once again, the Chieftan gets the drop on her and bashing her face in with a gravity hammer.

Kurt effectively dies after fighting with his fellow Spartans against an army of Covenant and only dying after a sneak shot to his body. That, and a hunter nearly slicing him in half.

LI and Anton from Halo: First Strike also die, not because of anything due to the Covenant, but some weird Slipspace anomaly.

I could go on, but my point is; Has any kind of group, or soldier actually beat a Spartan by skill and strength alone, or has every Spartan death happened due to circumstances that were out of their control,( i.e. The Covenant army on Reach, Slipspace fuckery, or a giant space warrior appearing out of nowhere to kill a group of Spartans.) and if so, when and how?

Also, small question at the end: Who would have won between Jai-006 and the Arbiter in Halo: The Cole Protocol?