I don't think sector closures are a slur on any Operational Atc people.
They are the Sad evidence of an organisation that has routinely failed to plan ahead.
They are also symptomatic of an Organisation that does not understand the reality that ATC is not "business", it is a PUBLIC SERVICE and part of the National / International Transport Infrastructure.
Trying to run it like a certain UK Privatised Rail Infrastucture Company will eventually lead to the same results. See the (ongoing) RailTrack fiasco.
Rgds BEX