The asshat in OP's image isn't representational of people who hire people in the average, every-day world.
In reality, most hiring is done by mid-level managers who have to interview dozens of people a week on top of doing their own work, and it's tiring and you don't get paid extra for it, and if you pick the wrong candidate your own ass is canned.
Yah, it really does help your chances if you show even a shred of actual desire to work there.
I don’t think I’ve ever gotten the hiring manager’s email address on any of the interviews I’ve done throughout my career, as communication is usually with the HR recruiter for the entire hiring process.
I've hired (low) dozens of people in public sector environments, and neither myself nor anyone on my hiring panels has ever cared if we receive a post-interview thank you. Maybe private sector is different, but I'd just as soon not have you clog up my inbox with thanks or make a post-interview pitch about your skills/excitement.
If you say thanks in the room, we're square. Likewise, I always thank people for their interest and time in the role.