we can't forget that the "free" players aren't actually that free, to sign them we pay them 1.5-2m per season more than the wage we'd pay them normally (which ends up costing us 3-4m per year) and upset the balance in our wage structure, which is already exploding without experiencing a freebie summer.
stealing freebies from the EPL is not cheap, Ozil would most likely become our highest paid player if we were to sign him, he's already at 8.25m per season and he'll be looking for a pay-rise not a pay-cut.
to put that into perspective, our starting goalie next season Woj is at 2.6m, our starting LB A.Sandro at 2.8m, Rugani 1.8m, Benatia 2.2m, Pjaca 1.2m, Berna 3m, Cuads 3.2, Mandžukič 3.5m. the salaries of Can, Costa and potentially Ozil are super-disproportioned to those, I can only imagine the fun renewal talks Beppe will have over the next few years.