Who says that is how it works at Sunderland, maybe it's public knowledge, but I haven't read that anywhere.
Likewise it's all too easy to say the players are rubbish, however most were free or extremely cheap, the only big buys are Altidore who I think was barely a few mil who scored 39 on 67 games in Holland, but had previously not done well at Villareal and a few other short spells in place. The biggest buy was a guy who played at Juve. He wasn't first team by any stretch but started around 20 games, another roughly 20 sub appearances in 2 years at Juve, after the first year they bought out his contract in full to make him completely a Juve player so they wanted him and kept him. I wouldn't call that championship class player to be honest.
There are plenty of cases where new players take time to adapt, and plenty of cases where lots of new players together takes time to adapt, put both together and you get a usually longer period of being rather crap.
It was Di Canio's lack of performances last year with the same squad, two wins, one against a woeful Newcastle then abysmal to the end of the season. By the end of this season we'll probably know who is good/crap out of the buys made(regardless of by Di Canio or the higher ups).
What I can't understand is O'neill somehow destroying Larsson, one of the single best/most effective freekick takers and brilliant right winger and Sunderland's only proper attacker who was at the heart of most of their wins, to turning him into a seemingly defensive midfielder, afaik Di Canio has been using him centrally while playing the selfish and inept Adam Johnson, who is probably one of the main reasons O'neill pushed him inside. Johnson is cack and Larsson was the best player in the team for a few years... he's not hopeless in midfield but Sunderland have looked SO much worse since neutering him into a almost holding role.