Here's the thing. The Kazon have been pirating other species tech and splitting off into factions which requires distance from parent factions for centuries. They are never going to evolve into creators of tech because they aren't designed that way, rather they are they are the master race of appropriation. Use of found (stolen) objects is their skillset. Intineracy and tribal social structures are their culture. So they didn't just start expanding from their homeworld last week when they decided to steal big cars, most of them have never been to their homeworld and they don't give a rats about it. They are FAR FLUNG because that's what makes them Kazon.
The Kazon were Trabe slaves.
Their independence was inside Cullah's lifetime, 25 years before Caretaker acording to "Maneuvers
". I'm thinking they were little better than monkeys when the Trabe found them.
As those ships break down, the Kazon arn't smart enough to build new ones, or seem to have the infrastructure to set up their own ship yards, but if they make enough "money" they might be able to buy a new fleet to replace the falling apart one that they have now.