Think you totally missed my point. David Moyes, Brendan Rodgers and Roberto Martinez all built good L1/Championship teams and overachieved with them. They all then secured high profile jobs that just weren't the right fit.
Moyes rescued Preston from slipping to the 4th before getting them to the championship and almost the premiership.
Rodgers got Swansea to the premiership and sustained it.
Martinez started the Swansea legacy by winning L1. He then took over at Wigan in the PL and kept them there for many years. In addition to this he won the Fa Cup.
They're all suited to "united type" clubs.
Eddie Howe also took over at newly relegated Burnley but the pressure was too much and he ended up back at Bournemouth. Some jobs are too high profile for managers and they can't hack it.
All those managers named above have excellent history and success in L1/Champ