I think the reason why people (myself included)) aren't higher on Brown is that while his opportunity looks great (especially if Rice is out) his opportunity has been great for most of his career. Its not like he's been stuck in bad offenses his whole career, other than 2023 when Kyler was out, (and Brown got hurt right when Murray came back) and he's mostly underachieved.
I think the idea of Hollywood Brown is better than the actual product (which is similar in some ways to Calvin Ridley, other than Ridley's 2020 season) I see a guy who has become a less effective player every season of his career since his rookie season, and less efficient the more he's been used. He's flirted with some good fantasy numbers for sure, but its never sustained, and unless we want to argue that 3 different coaching staffs were using him wrong, but Andy Reid will unlock him (not impossible, no sure thing) I think he's a guy where he's likely to continue to disappoint, especially if Rice's absence pushes him up draft boards.
I think Rice showed more his rookie season than Brown ever has. That said, as mentioned, they have played very different roles. We don't know if Rice is limited to that, but I think we have enough evidence (5 years) to say Brown likely is. I'm gonna be driving the Kelce bandwagon if Rice out. I think Brown and Worthy likely cannibalize each other, unless I'm way too low on Worthy.