I feel like it's probably a lot harder to make a toddler/preschool show appealing to adults while still appealing to its actual target audience, versus kids' shows aimed at school-age children or tweens.

Some shows definitely pull it off, though, it's just rare. Haven't seen Bluey due to neither having kids, nor having young relatives or friends' kids in the right age bracket for it. Arthur pulls it off, though, imo.

Though Arthur tends to be kind of like, an "all-ages" kids' show, if that makes sense? Like, it's a solid choice for a preschooler, but it's also enjoyable for older kids closer to the main characters' actual ages (iirc Arthur is in 3rd or 4th grade). Kind of in a different category than something like Dora the Explorer.