I did a wine trip out of SEA with six people and we were actually somewhat surprised at how tight it was with our luggage and a few cases of wine, because common wisdom in the rental industry is that minivans have lots of luggage capacity. If the Escalade/Navigator is the ESV (or Navigator L) version, which the photo does make it look like (not that I completely trust the photo...), then I actually think it would have more room than a minivan.

If it's not the ESV/L version, though...yeah, you're probably right. I've never paid attention to the Prestige Collection SUVs enough to notice what model they are.