Like I said, how many in any industry would do it? And the ironic thing is if he did do the overachieve with lesser resources he'd have got mocked for not winning anything, ala Pochettino at Spurs.
The only bit of "luck" he got was getting the Barca job so early and even that came through smashing it with the B team as
@Daydreamer said, if he was just some chancer who fell into the right place at the right time due to his name he wouldn't have lasted long at Barca and he certainly wouldn't have got the jobs he got after.
Would he have been successful in a so called lesser job? Well I guess it depends on what you define as success, if you expect something ridiculous like him taking over Leyton Orient and winning the treble then ofcourse he would "fail" but (if he had to do this route to get a big job) could he have done a great job scaled for the budget and club size like Tuchel and Klopp both did at Mainz, Sarri did at Empoli, Pochettino did at Southampton and De Zerbi is currently doing at Brighton to then get the attention of the big boys? Absolutely yes.