I think you're misinterpreting what he means. Every couple years you should be just evaluating whether you're taking on more responsibilities or you're working

I think you're misinterpreting what he means. Every couple years you should be just evaluating whether you're taking on more responsibilities or you're working on genuinely more difficult/complex problems. If you're not, you need to show aptitude at your current company so you get placed to do it, or if it's the case that the company is the issue and not you, then you should consider moving on. If there is a path of progression for you in terms of responsibility and difficulty of work, then by all means stay at a company for several years. Within this framework it doesn't mean you'll necessarily be moving companies every 2 years.