Just playing devils advocate here, but... Winning a lower division for the first time in a clubs history, when you have the most expensively-assembled squad, does not constitute success, does it?
... devil indeed ... perticularly leaving the immediately following words out of the quote ... ... success is relative ... whilst it might be expected to win a lower league if you are able to assemble the most expensive squad in it, you do still have to see it through and, as often quoted, there are 'no guarantees in football' ... but it should not come as any great surprise to win that title in such circumstances ... the better measure was the bit you omitted ... Ranieri then took Monaco to finish second in the top tier the next season ... He would not have been my choice ... but his managerial credentials do give cause for some optimism in terms of the immediate goal ... finishing on a par with (hopefully bettering) last season's finishing position ...