That’s just it; they rarely go for currently popular artists in the modern Super Bowl halftime show era. It’s almost always some sort of very popular act with a long career, but never one at the height of their popularity. It’s very calculated to appeal to a very broad audience- I think the idea is that had they put Rihanna as the Super Bowl XLII (2008) headliner, she’d have been popular among a small set of viewers, while doing it in 2023, nearly everyone’s heard of her and heard of her music by now.
That, and they usually have a large enough catalog of hits to choose a medley of non-offensive ones that people will recognize. I mean, we didn’t hear Rihanna’s “S&M”, which IMO is one of her better/more catchy ones, probably because it would offend people. It might have been harder to pick a list of her songs that were hits AND unlikely to offend anyone in 2010.