Theoretically there is no hierarchy. The Pope is just the bishop of Rome. He owns his preeminence from being the guardians of the keys to heaven through being the canonical successor to Ss. peter and Paul.
When the theoretically equal episcopal offices of the Church were organized into a hierachy by the Emperor Charlemagne in the 780s - the title archbishop is an invention of his advisors - the archbishop was intended to supervise the bishops of his diocese. The archbishop was the head of the council formed by the bishops of the diocese - the
major et sanior pars in all matters of dispute. In fact, the relationship of an archbishop to his suffragans was identical to that of the pope to all bishops. As in all organisations there was considerable internal strife and the Pope definitely undermined archiepiscopal authority. But archepiscopal sees were always far wealthier than suffragan, thus producing more actual power, had higher civil and ritual status (capitals of Roman military dioceses, more and more powerful saints).
IF you look at orders of prcendence for the Holy Roman Empire you notice that archbishops ranked over bishops. If you looka at the plurality practices you'll find that most suffragan sees were adjuncts to its episcopal (Mainz held Würzburg, Cologne held allof its suffragans with the exception of Münster, etc etc).
The workings of the contemporary catholic Church is rather irrelevant to the question as posed.
The cardinals. BTW, were originally the priests of the parish churches of Rome, ie the men that elected the Pope as bishop of Rome.
And the bishop of Rome is precisely that. His opinions ought really not to be taken seriously by anybody else - come to think of it.