That's the goal: A fun new Karma name to look forward to.
You can get one Karma a day. Even the top users aren't going to hit 10,000 for 3 years, and the majority of the userbase for maybe decades, assuming the site even lasts that long.
This sounds entirely like adding ranks for its own sake. There's no privileges associated with user levels after 500 Karma, and you have proposed none for these additional levels (not like any are given at any prior levels). If there was a board for the new level, that barely constitutes an award, considering the present user level boards are pretty much barren.
What exactly is there to "look forward to"? An arbitrary counter incrementing for the first time in years, in addition to the other arbitrary counter that increments on a daily basis? I imagine not even the higher-Karma users actually give a damn about their Karma, they just visit and use the boards frequently.
See me on Discord! ^.^ Eevee's Mystery Dungeon: https://discord.gg/fexbndS