That person doesn't know what they're talking about. Netflix is adapting plenty of books; right now Tiny Pretty Things, Dash and Lily, and Cursed are their biggest YA adaptions that are hyped, not to add their adaption of Leigh Bardugo's Shadow and Bone & Six of Crows series coming out this April are highly anticipated by teens. Hulu also has the rights to Throne of Glass, another highly anticipated YA adaption, so there's still YA movie craze out there, albeit more towards streaming than theatrical releases