In the old days the CIO was often a board member - as important as business area executives.
Then came the age of internal procurement processes and the IT-departments were sent to the boiler room and told to show up only when asked to. Business will tell them what will be done and IT could decide how it should be done - but do it fast and much cheaper and not complain about architecture and such things. If IT did not deliver on SLAs they had to pay penalties (sic!). Business often enough ganged up with vendors who understood how easy it was to implement new things - just add some servers and it will run - integration can come later.
I have never bought this artificial departmentalization. As technology is the mega-enabler for most change - and business should understand that better together with the realities in the legacy systems. CIOs should work much more closely with business also to be more proactive drivers of change. Horizontalization is the answer to better agility - not making silos even more isolated.