Sunderland are spending heavily in an attempt to ensure they last longer than a single season in the Premier League. The club’s transfer business has raised eyebrows. Sunderland’s promotion team comprised a mix of academy graduates and low-cost acquisitions — the starting XI for May’s play-off final victory against Sheffield United required less than £10m to assemble. Two months on, Sunderland now have the most expensive squad in the club’s history. Xhaka is the club’s seventh signing in a month. Add Roefs and some assumed agent fees and transfer levies, and we land at a gross spend this summer of £130m. Sunderland are the seventh-highest-spending Premier League club this window, only trailing the traditional ‘Big Six’. On a net basis, including the Roefs deal, they’re this summer’s eighth-highest-spending club in the world. After accounting for sales, alongside fees spent on Wilson Isidor, Milan Aleksic and Ahmed Abdullahi since the start of their financial year last July,...