They aren't, though, they're just kind of throwing random breeds together because they are "cute".
I'm honestly curious... what are you basing this on?
Breeders of ALL kinds have good and bad motivations behind their breeding, whether pure, cross, sport, work, "designer," whatever. I think it's just as rude to dismiss ALL companion mix breeders as "throwing random breeds together because they are cute" as it is to lump ALL show breeders together under an umbrella like "only care about looks/it's a beauty contest."
Most of the doodles and cockapoos in particular that I encounter have come from breeders who seem honestly motivated to provide people with good family pets. Sure, there are some pretty weird random mixes out there, too (bernerdoodles and cockers/cavaliers mixed with everything under the sun, I'm looking at you), and that has gotten out of control... but there are out of control breeders across the spectrum of dogdom.