It’s not stuck together. You have no metal at all and that’s why it was glued in place.

Technically you have a reducer moulding but the person who installed it did not do it correctly.

The metal u channel acts like a clamp to hold onto the center wood channel on the bottom of the transition strip/threshold/reducer moulding.

Moving forward, I wouldn’t worry about buying a new moulding. If you did install the U channel you would probably need to cut the floor to have the proper gap. I recommend just cleaning off the glue and then gluing it back in on just the taller floor side. While not perfect, it is good enough and will be better than you had before.