I can’t tell you about this specific jump in quality/price, but about a similar experience.

I had an AKG K701, went into a store and tried a random headphone with a ludicrous price tag - 5500€.

This particular difference was so mindblowing that I stopped listening to music on headphones entirely for about 12 years, until I could afford my own hd800s, hoping it is „good enough“ compared to how I remembered this specific headphone. (Turned out to be a Stax, maybe SR 007 or 009)

The HD800S is worth it if you care about stage and natural timbre, it’s not as precise as some planars in its price range, but just smooth.