Why have they fallen out of favour? Probably because barely anyone even makes them anymore. Hunting for bigger margins, manufacturers have flocked to crossovers to the extent that they've started using the names of sporty coupes (Puma, Eclipse) for dumpy crossovers, which still somehow seem sporty and successful enough for people to want them.
Wagons and minivans are only cool to nerds, but crossovers get the sort of Action Vehicle look that sells them to people without any family wagon aspirations being too obvious (while also not having enough space for hauling anything). And no R&D money needs to be directed to developing AWD, adventure plastics are enough.
I get it, I wouldn't want to try to get a kid and kid stuff into a two-three door car anyway.