The Sherlock Holmes stuff isn't really the main issue with localization. It's the fact that Ryuunosuke is from Japan and very much implied to be Phoenix's ancestor and the localization takes place in the US.
The other factor is that its a spinoff of the AA series and AAI did poorly in its localization.
Making references to pop culture isn't going to be something that is going to infringe upon copyright. Plenty of canons do this without having to pay royalities. It's making actual use of the work, like if a case played out a post 1923 story. A reference falls under fair use.
Re: ACE ATTORNEY
The other factor is that its a spinoff of the AA series and AAI did poorly in its localization.
Making references to pop culture isn't going to be something that is going to infringe upon copyright. Plenty of canons do this without having to pay royalities. It's making actual use of the work, like if a case played out a post 1923 story. A reference falls under fair use.