There's a major reason why Homelander never uses his full powers on The Boys, as the comic book's writer once explained the danger he faces by doing so. In an old interview, Garth Ennis, who co-created The Boys alongside Darick Robertson, shared that Homelander is always holding back his considerable power because he knows if he ever fully unleashes it, Vought-American will drop a nuclear bomb on him.
Homelander's entire existence is based around the Vought-American PR machine that makes The Boys Supe their most marketable and important hero in existence. However, in the comic book series, Homelander's origin is all a lie. While the general public believes that, like Superman, he fell from Earth and was raised in humble beginnings, Homelander was actually the product of Vought-American's experiments, as he was kept in confinement with a nuclear weapon ready to go off if he ever lost control. That traumatic origin has prevented Homelander from ever unleashing his full powers, as he is still very much worried about the threat at the hands of his creators.
In an interview with Newsarama back in 2008, The Boys co-creator Garth Ennis was asked about Homelander's racism on display through a recent arc at the time. Ennis responded by calling Homelander "an almost entirely negative character" that understands he can have whatever he wants as "long as he doesn't push his luck too far." The comments would lead Ennis to admit if Homelander ever did push that luck to an extreme or lost control, Vought-American would "chuck a nuke at him."
Check out the full comment from the interview with Ennis.
Yeah, well the Homelander to me is an almost entirely negative character. He is really just a series of unpleasant urges kept in check by his own intelligence, which is enough to understand that he can have anything he wants so long as he doesn’t push his luck too far. ‘Cause if he ever tries to exploit his massive power and strength and simply run riot, they will eventually just chuck a nuke at him.
Homelander never pushed his powers to their limit until the end of his time in The Boys comic, where after the public believed he committed some horrible atrocities (which was Black Noir pretending to be him), including eating a baby, he killed the President of the United States and took on his clone. While Vought-American or the U.S. Army didn't opt to drop a nuclear bomb, they did send in tanks and other deadly weapons, which resulted in the death of Black Noir after he murdered Homelander.
Vought-American doesn't seem to have the same failsafe for Homelander in The Boys television series, as the Supe operates with less fear about his potential demise at the hands of his creators. However, in the comics, Homelander held back his power, knowing full well that if he lost control or made the wrong move, Vought-American would end his reign by dropping a nuclear weapon on him, as they threatened for years before he was revealed to the public. Homelander is a deranged Supe, but even he knew not to push his powers as it could have cost him his life much earlier in The Boys comic book series.
Source: Newsarama - Archive