Has Neymar been a failure at Paris St.Germain (PSG)? When the French champions made him the most expensive footballer in the world by breaking the bank and activating his release clause to bring him from Barcelona, they wanted European glory. Neymar, admittedly, has failed to deliver it yet despite PSG making it to their maiden Champions League final this year.Neymar, despite scoring goals and helping the team to multiple domestic titles, has been a bit of a mixed bag in Paris. The footballer has suffered with injuries and blighted his reputation with his erratic behaviour.But his spell in PSG continues, and it isn't yet time to declare him a failed big-money footballer. However, history has seen many footballers who fall into that category.Footballers are, after all, one of the most prized commodities in the postmodern world we inhabit, and the best of them are traded for huge sums by clubs.For some like Juan Sebastian Veron who joined Manchester United for £24.3 million way back in 2001 or Luka Jovic who joined Real Madrid last season for £53.5 million, the price tag can weigh very heavy.In this article, we will take a look at ten such big-buy footballers who failed to live up to their expectations.10 big-money footballers who failed miserably:#10 Robbie KeaneRobbie Keane.Big things were expected of Robbie Keane when he was bought by Liverpool from Tottenham for a whopping £20.3 million back in 2011. It is safe to say that Rafa Benitez's gamble did not pay off as Keane went back to London to the club he came from after spending just six months in Merseyside in a spell in which he almost forgot where the net was.Robbie Keane has suggested Rafa Benitez went back on his word during their time together art Liverpool."When I went there [Liverpool] I was told myself and Torres [would start] and Stevie would drop into the midfield.” 🔴 pic.twitter.com/SBFkt8HEIz— Anfield Watch (@AnfieldWatch) April 22, 2020#9 Juan Sebastian VeronJuan Sebastian Veron.When Juan Sebastian Veron arrived at Old Trafford, he was deemed to be one of the best footballers in the world. Sir Alex Ferguson was looking for some world-class guile in his midfield to take Manchester United back to the top of Europe.Veron was the most expensive English transfer of the period. It is safe to say that the legendary Old Trafford boss did not get it from Veron in the 82 matches he played. The skillful midfielder struggled to adapt to the faster pace of the Premier League and also suffered a serious injury in his second season.He was promptly moved on to Chelsea where he struggled again before going back to Italy where the Argentinian had made his name originally.Ex-Red Juan Sebastian Veron reflects on his fond memories of Old Trafford: https://t.co/CRSbgZbGMz #mufc pic.twitter.com/c5oiAXHYgm— Manchester United (@ManUtd) April 18, 2016