Why were the writers so scared...

...to have the talismans stop working?

The whole series, one of the monsters walking up to a door with a talisman on the wall and just ignoring it was right there! It was the clearest way to up the stakes and ratchet the tension, and instead they did this weird thing where the MiY just stole everyone's talismans in the final minute? Which accomplishes the same thing in a far stupider way?

And now we get treated to a final season which hinges on the notion that literally nobody kept an eye on the only things which stands in the way of them getting eviscerated every night?

Literally just have the talismans stop working. Show the MiY going around doing something subtle and witchy to the talismans - not taking them. Then end the season on somebody's house at night. Everyone mourning and celebrating and trying to figure out what they do with the bones. So distracted by the day's events that they don't notice one of the monsters walk up to the door, turn the handle, and open it. Cut to black on that, season over.

It felt like the show wanted that outcome, but thought just turning the talismans to duds was too obvious or something. Instead we got the BiY and MiY exchanging vagueries which was the definition of an anticlimax.