Bill Zebub
“It’s probably Matt Mercer’s fault.”
Well, the problem is that the class originally called "Thief" has changed in both name and function over time in D&D multiple times, and who some third party used as their inspiration has changed with it. The farther you go back, the less distinct "Thief" was other than in having certain skills.
If the OP was making an argument about 1e that should have been declared. If they meant the thief archetype in general they should have explained what they were including/excluding in that definition.
That's why upthread I suggested the thread title should have said "Skill Monkey" instead of "Thief".