The implication the writers were trying to give throughout the entire show is that Homelander is a weak coward at his core. His powers are the only thing that make him what he is. You take them away and he's a pathetic being.
The way he died was borderline foreshadowed since the very first episode, and then COUNTLESS times throughout every season. On his knees begging for his life because that's who he's always been, he was just hiding behind his powers.
It's pretty straightforward stuff. I'm surprised so many don't understand why he went out like this. As bad as the show has been at times, this ending made total sense.
> Shameless ad for Vought Rising
> Built up Ryan just to abandon his arc
> Built up Marie Moreau just to nerf her
> Soldier Boy gets put him back on ice
Genuinely awful final season of The Boys