There is still room for city employees and other vendors to exert some control over higher level IT services and applications. But the core infrastructure needs to be under the control of a single competent vendor.
And the incentives are to keep it that way. As long as MS's PS team can make more money from one whale of a customer than they can supporting local districts, expect that this will remain.
Such that I don't think it is excusable to say "if only they had paid the professional services."
I am concerned with "best practices" in our industry, though. Too many of them are not geared to wide adherence and have fantastically bad failure cases.
Random think tanks doing thought leadership on CNN or at Brookings will jack themselves off to the notion of "online warfare" and whatnot, but those guys can barely type, let alone write cohesive policy.
I've been on both sides of this - both in the policy making world and in the private sector tech world - and cases like Oakland keep happening in a daily basis everywhere and will keep happening forever.
Would you apply the same logic to road infrastructure? Why hire those licensed engineers...