Exactly what Tim just said. Even witnesses not in the top 100 have to work their asses off. It's full time responsibilities, always on call. I've got email notifications when a service my team offers stops working, I plan algorithms to help others' projects while waiting on appointments, ordering food, whatever that grants me a minute to sit down and think. I'm in the 120s. It's not easy and it shouldn't be easy to get votes. A good portion of witnesses who got up there aren't the original insiders and legitimately deserve what they achieved. If it wasn't for witnesses there'd be no third-party services, there'd be no projects, there'd be no communities, etc.
Further, without the prospect of rewards there'd be no way to attract high talent. For the @guiltyparties witness with its 120something rank there is a solid, highly educated, professional team with a project manager, a blockchain developer, and entrepreneurs. We started this to build on the STEEM blockchain. There are other witnesses out there who are witnesses for a living. While they receive rewards, the amount of effort and time they dedicate to it equates to what they would make in a full time job. Pretty much anyone who runs a witness successfully has the skills to get a high-paying job in the IT sector. Those who don't can't even get set up.