People have been told for their entire lives that job interviews are high-stakes situations. Even if it's a job-seeker's market, it's usually a stressful situation. You're in someone else's office, generally outnumbered, and most of the interactions are the kind that make introverts sweat.

I don't fault developers who come across as nervous when I interview them.

There are always more jobs, but not always of equal desirability. Knowing that this company is the only one in the perfect location, on a project that fascinates you is about as high-stakes as it gets.

"More jobs" doesn't really matter if you really want to work at a specific place.