Tbf, the squad they came up with was for the most part an above average League 1 squad, so they needed players they knew could perform at this level.
That's their modus operandi; spunk loads on a new squad whenever they need one, because they don't have to think about cash turnover. It's anti-competitive, in my opinion, and very bad for football generally when club(s) can have a budget that way outstrips that of rivals and isn't in any way tied to success on the pitch or a canny turnover of players.
As for how they're doing; all you can say is they seem to have a better clue than Birmingham. At least they try to sign the players that they actually need / suit how they play, even if at massively inflated prices.