The two clubs have different footballing structures and operate in different environments. We don't know that the Friedkins personally drove the changes at Roma, and we've been told numerous times that their MO is to put people who know what they're doing in place to make the relevant decisions rather than getting involved themselves. I'd have thought if they felt the decisions we were making weren't meeting their ambitions they'd be more likely to get rid of the people making the decisions rather than those benefiting from them.
