It's going to depend a lot on whether or not it's actually any good (in the sense of being enjoyable, since it's a given that it's not going to be a cinematic masterpiece). Generally speaking, Illumination has managed to break that milestone pretty consistently (Hop is their only film that didn't), so presuming it's roughly in line with the quality of their other movies, I expect it probably will, especially with such a recognizable IP powering it.
I don't think comparing it to Detective Pikachu probably is the most appropriate. As much as Pokemon is a massively successful franchise, Detective Pikachu very much was not a typical Pokemon movie, so it's not surprising that it didn't draw the kind of attention a regular Pokemon movie would. Meanwhile, I expect the Mario movie is going to be pretty firmly in line with typical Mario fare (if not the previous examples of Mario movies), so it'll likely appeal to most people with an interest in the franchise beyond the games (and the world of Mario merchandise does quite well for itself).
hera posted...
it's going to be a commercial success but a critical flop
This seems extremely likely.