A guy at a coffee shop in Boise told me to fire my best employee

I was grabbing a coffee last month and got talking to another business owner. He asked about my team and I mentioned my lead tech, Jake, who's been with me for 8 years. This guy looked me dead in the eye and said, 'If he's been there that long, you need to let him go before he gets too comfortable.' He argued that long-term staff stop trying and cost more money. I was shocked. Jake is the reason we keep our big commercial accounts happy. That advice felt so wrong and short-sighted. Has anyone else gotten advice that just seemed to miss the whole point of building a real team?