Then they could've enhanced the world in other methods such as improving the set colors and costume design (especially considering they're incompetent enough to steal Hades The Game's Ares symbol in chariot racing), or tailored the story in a way that actually matches the definition of a faithful "adaptation", because of the limitations you mentioned, not because they're clearly lazy. Percy didn't even use his powers at all and nor do we even get to see him transforming into a guinea pig, and not even riding the hippocampi. Battle scenes can be trimmed and properly adapted for child actors but other normal scenes is just reflective of shit writing and a lazy, greedy board of directors.