Case against Becky Lynch winning 2019 Women's Royal Rumble match
There are a few legitimate reasons for Becky Lynch not winning the 2019 women's Royal Rumble match.
Firstly, it is possible that she defeats Asuka to regain her Smackdown Women's Championship. World Champions do not participate in the Royal Rumble match. Becky Lynch cannot win the match if she is not in the match.
Secondly, the story may be served better if Becky Lynch is not in the match, even if she loses to Asuka. Part of the reason Becky's rise was so meteoric was because it was organic. The fans supported her because what she said was true; she had been passed over repeatedly whilst others got opportunities. Why not lean into this sentiment?
Becky Lynch not being a part of the match would create a groundswell of support for her, and release a whole lot of vitriol on the WWE. If done properly, it could artificially recreate the Daniel Bryan 'Yes Movement' storyline, and make her an even bigger babyface.