Except they don't. Here's a list of all protection rings, cloaks, and bracers from the more popular modules. I excluded items belonging to playable NPCs or NPCs where it was unlikely the PCs would ever get them unless they went full murder hobo and killed everyone in town. The +3 items don't show up until your at or past name level, and the only +4 item is the final module of facing Lloth in GDQ series.
The modules certainly don't have items to justify -7 AC for a level 7 or so PC. Not even for a level 15 PC. Again, assuming you went through all the right modules and found all the best magic items and one PC got them all. I was surprised to see just how few cloak of protections there were.
Item | Modue |
ring +1 | A1 |
cloak +1 | A1 |
ring +2 | A1 |
bracers AC 6 | A1 |
bracers AC 6 | A1 |
cloak +2 | A2 |
bracers AC 4 | A3 |
shield +1 | B2 |
plate +1 | B2 |
ring +1 | B5 |
ring +1 | B5 |
ring +1 | B6 |
ring +1 | B6 |
ring +1 | C1 |
bracers AC 4 | C2 |
ring +3 | C2 |
ring +3 | D1 |
ring +3 | D2 |
ring +1 | D3 |
bracers, DM fiat | D3 |
ring +3 | D3 |
ring +3 | D3 |
ring +3 | D3 |
ring +1 | D3 |
ring +1 | D3 |
ring +3 | G2 |
ring +3 | G3 |
ring +1 | I1 |
cloak +1 | I1 |
bracers AC 4 | I1 |
cloak +2 | I12 |
bracers AC 6 | I12 |
cloak +3 | I2 |
cloak +2 | I2 |
ring +3 | I3 |
cloak +1 | I4 |
ring +1 | I5 |
ring +1 | L1 |
bracers AC 9 | L1 |
ring +2 | L1 |
bracers AC 4 | L2 |
bracers AC 8 | L2 |
bracers AC 2 | L2 |
ring +2 | L2 |
ring +2 | N1 |
ring +1 | N1 |
ring +4 | Q1 |
ring +1 | Q1 |
ring +2 | Q1 |
ring +2 | Q1 |
ring +3 | Q1 |
bracers AC 3 | Q1 |
ring +1 | S1 |
bracers AC 6 | S1 |
ring +1 | S2 |
ring +1 | S3 |
ring +2 | S4 |
ring +1 | S4 |
bracers AC 5 | S4 |
bracers AC 7 | S4 |
ring +1 | T1-4 |
cloak +1 | T1-4 |
ring +1 | T1-4 |
ring +1 | T1-4 |
cloak +1 | T1-4 |
cloak +2 | T1-4 |
ring +2 | T1-4 |
ring +2 | T1-4 |
bracers AC 6 | T1-4 |
bracers AC 3 | T1-4 |
bracers AC 3 | T1-4 |
ring +1 | U1 |
ring +1 | U2 |
ring +1 | U3 |
ring +2 | U3 |
bracers AC 4 | U3 |
cloak +1 | UK2 |
ring +1 | X2 |
ring +1 | X2 |
ring +1 | X3 |
ring +2 | X3 |
ring +1 | X4 |
ring +1 | X4 |
ring +1 | X5 |
ring +1 | X5 |
ring +1 | X5 |
ring +1 | X5 |