The myth of "hard work = high wages" is one of the most pernicious and persistent of American lies, I'm afraid. It has never been the case for as long as the country has lived.
Still, these people will want to keep these high-paying jobs, and they know there are people lined up around the block to replace them, so to imply that the company is going to be saddled with unperforming employees is ridiculous.
Conversely, paying employees too little would make them indifferent to their jobs and difficult to replace, naturally removing incentives to work hard and deliver value to their employer.
This does ignore the point that poorly paid employees might work hard to get bonuses or promotions, though, and well paid ones might not need them. I don't know whether these sorts of jobs get performance-based pay, or come with opportunities for career advancement.
No, the actual incentive to work is that you get homeless, sick, and hungry if you don't. This is in contrast to other countries, where the unemployed (especially the long-term unemployed) receive social support. In the USA, people on parental leave from white-collar, salaried jobs don't even necessarily get paid -- to avoid incentivizing pregnancy, you see.