If you were a top-tier developer, there was a >0% chance that you would be super excited about the product because you realized the pain point that it would solve for you if you were building a real-time product at another company. And that excitement or lack thereof was a useful litmus test for Firebase specifically.
I agree that "excited about our company" is not something you get up front if you are interviewing at a company that is building an on-demand AI marketplace for ML-optimized scooter rental office spaces.
For such a small team, and an early-stage company, I believe it's critical to hire people who are absolutely excited about the mission. They're not simply looking for "an employee," but a partner who believes in what they're doing, coupled with having the ability to help them do it.
I wonder if "excitedness about the company early in the interview process" is in any way indicative of on the job performance later on.
It always seems weird to me. I barely know you- why would I be excited? Ask me at the end of the onsite after I've talked to a number of people across a variety of roles, seen your office, heard about the work, explored the culture, etc etc.
During the initial screen, I really only know about your business, which is not the biggest factor for me.