They have a different study for long term reliability. It's called "Dependability Study" I believe.So, yeah, I don't buy the marketing gimmicks and hype. It's mostly marketing lies, no long-term testing, and other promises that rarely meet the hype.
The one in the OP is just overall satisfaction measured after the first 90 days of ownership. Since it's for brand new cars, they don't have a crystal ball to tell you how these cars will fare many years down the road.
So yeah, this is of limited use to most people, but it's not like they're hiding what this is.study is essentially a measure of brand appeal
The study, according to the release, asked owners to consider attributes, “ranging from the sense of comfort they feel when climbing into the driver's seat to the exhilaration they get when they step on the accelerator.”
A fresh look can make a big difference.
The J.D. Power study is based on responses from 110,827 owners of new 2021 model year vehicles surveyed after 90 days of ownership