While it's tempting to try and quantify "quality", that's easier said than done. I've played a lot of guitars in my time, and I would absolutely assume that a $500 guitars - especially an acoustic - to be inferior to a $2000 guitar of the same type. I would probably not always be correct, though.
The problem is that I'm a seasoned player who has 40 years of experience knowing how a guitar should sound, feel, and play. Because of that, I can usually tell a $500 guitar from a $2000 guitar with my eyes closed. My daughter, who has been playing for maybe a year or two, absolutely cannot tell the difference. For her, there is no benefit to spending big money on a guitar. I've tried experiments and had her play multiple and she has never gravitated towards the nicer guitars because the benefits are so far beyond her.
But here's the rub - as Tom pointed out, things are different than they used to be. When I was a kid, playing a "cheap" guitar would often result in endless frustration due to an instrument that couldn't stay set up or even in tune. These days I bought her a used Takamini acoustic for $500 (probably $800 new) that is mind-blowingly good, comes with electronics and even has a tuner built in. That guitar is amazing for the price, and without the electronics it would probably be $500 new. Can I tell that it's not a $2000 guitar? Absolutely. Can she? No.
That, IMO, is the big deal today. Now, where things get dicey is when the price goes up a bit on those import guitars, and suddenly when you get into the $1,000 range, the differences between them and a $2,000 are far less obvious and probably get into the bling more than the playability and timbre.
What's worse is that when I went hunting for a $3,000 Taylor, I played literally hundreds of them until I found the one. Even better, it was a $2,000 model in a sea of $3,000+ guitars.
Price isn't everything. Every guitar is different. Play them all and buy the one that sings to you.