I'll stop too after I bring this up again from a previous post I made in this thread:
"In Russell's case, he actually is an experienced rock singer. I've seen people make the argument that it was more of a factor of him not having the range to sing something like Les Miz. Nicole Ackman, who's my colleague at BroadwayWorld in our area of residence, once said on Twitter: "I don’t *love* Crowe’s Javert, but I don’t mind it. (I blame Hooper for my issues with the way the character is portrayed)".
If you actually look it up, Les Misérables was actually Russell's first time in a film that was a genuine box office hit since A Beautiful Mind 11 years earlier. I don't know if audiences for a while were kind of turned off by the troublemaking incidents he committed from him verbally abusing a producer after BAFTA in 2001 (which famously cost him a second consecutive Oscar) to throwing a telephone at a man in the Mercer Hotel in 2005. Although with Les Miz, that was an ensemble piece, so the marketing pressure wasn't all on him in particular."
To your point about the movie having enough commercially viable actors in it with Hugh Jackman and Anne Hathaway (the latter of whom was especially showcased a lot in the advertisements with her rendition of 'I Dreamed a Dream'
, that was certainly the case with Into the Woods. The filmmakers had several prominent film actors in it such as Meryl Streep, Emily Blunt, Anna Kendrick, Chris Pine, and Johnny Depp. Yet, they managed to find room for James Corden (who at the time, wasn't as well known as he is now) to play the male lead.