What made Anthony the Great more significant than Paul of Thebes? As I understand it, it was Paul who became the first Christian hermit who went into seclusion to lead an ascetic life heeding the words of Jesus about the rich young man who sold his possessions and gave to the poor.
Can anyone please explain why Anthony is more "famous" and historically significant than Paul?
Essentially because of Athanasius produced a more widely circulated book than Jerome.
Athanasius' Vita of Antony enjoyed wide circulation in Greek and in Latin, and it became both well-known and imitated.
While strictly speaking 'father of all monks' is erroneous, Antony did become an influential leader of early monasticism, especially by pioneering a genuine anchorite lifestyle. Later monks sought to model themselves on and emulate Antony, hence his importance.
Jerome's Life of St. Paul the first Hermit didn't appear in Latin until after the Life of Antony had been translated into Latin. So in terms of literary influence, Jerome missed out. It also never really became as popular. Thus, the reputation of Paul was not as well or as widely established.