The question now is whether RNZ lost a watchdog against crass commercialism and sponsorship. Many will hope his replacement Paul Thompson - the editorial head of Fairfax NZ who starts in September - will be more forward-thinking.
Cavanagh, who was focused on maintaining the core business within limited resources, believes RNZ should stick to its knitting rather than finding new strings to its bow.
Pine tree
RNZ is a cultural institution so a departing chief executive won't be seen off with morning tea or Cavanagh shouting a few pints and sausage rolls at the pub across the road.
RNZ staff organised an audio link up between the Wellington, Auckland and Christchurch offices so they could sing in unison. Here are translations of the waiata to Cavanagh, as supplied to RNZ staff.
E tu kahikatea:
Stand tall, like the white pines (roots systems need to interconnect).
You give to me and I give to you.
And between what we have.
We will be strong together.
Karanga tia ra:
Travellers we.
Travellers we.
With provisions.
From the Islands of our ancestors.
We speak here at our sacred entrance.
A greeting of love.
For you are our family.
To you we give greetings.
Expressions of love.
History lesson
When National won the 2008 election, Broadcasting Minister Jonathan Coleman treated RNZ with disdain reflecting an attitude in Cabinet.
Then came the global financial crisis and National suggested sponsorship to fill the gap in funding.
RNZ supporters saw the government's plan as political assassination of a fair-minded public broadcaster.
But one source familiar with National policy said: "They just didn't think maintaining public radio and RNZ's role was important."
National later appointed former lobbyist Richard Griffin as chairman of the reconstituted board which demanded change, clashing with Cavanagh.
After a public clash between Coleman and Cavanagh over sponsorship of RNZ - in early 2010 a genuine grassroots campaign to "Save Radio New Zealand" was launched.
The Facebook campaign revealed the degree to which RNZ had a passionate following. But it became focused on swipes at National and the perception grew that the campaign had been taken over by the Labour Party.
Under Helen Clark Labour had felt a sense of government ownership of the state broadcaster, but overall funding still slid.
In late 2008, the Labour-appointed chairman of RNZ - Brian Corban - reappointed Cavanagh for a five-year term.
It was just a few months before National's widely predicted election win, and while the lack of consultation did not breach rules, it did breach conventions, said a well-placed source, and this added to the historic antipathy to RNZ inside National.
Changes needed
RNZ does remarkably well ensuring radio debate about important issues and avoids restrictions that would be imposed if it were linked to advertising.
But it's staffed by hard working people aged 50-plus and content appears to be aimed at people just like them.
Some content is extraordinarily strong. But RNZ has done little to change to reflect small business people and their concerns or working class people - an audience left to Newstalk ZB and RadioLive.
New formats have been tried. The afternoon show with Jim Mora including an opinion segment that is pilloried on Twitter for often featuring older people with conservative or trivial views.
The Sunday morning segment with Chris Laidlaw - in public radio prime time - is cautious and pedestrian and caught up with the Wellington chattering classes.
Its political comedy programme Down The List should poke a finger at the Government, but displays a bias to Labour.
The young ones
One new innovation that has made some headway is the new youth-oriented online project.
The initiative harks back to the days when Labour set aside radio frequencies for a youth radio network, but abandoned the idea due to cost and lobbying from commercial operators The Radio Network and MediaWorks.
Labour loaned the frequencies for Kiwi FM, which has since pulled back from its 100 per cent local playlist to 60 per cent.
In any case, the costs of a website - albeit with some audio content - are much less. RNZ has recently hired three staff to run the website aimed at people aged 18-30.
There is some logic in the website - tipped to be launched later this year. RNZ has an ageing audience and desperately needs to draw young listeners.
The other argument is the new online project might absolve RNZ from catering to the young in its mainstream programming.
The alternative station Bfm will be involved.
New chief executive Thompson is said to be enthusiastic.
But some are sceptical whether the idea of a young person's hub will be attractive now people have developed their own personal line up of media and websites and don't feel obliged to be aligned with a state-owned website.
For many the new innovation is what RNZ should have done 10 years ago.
Christie Almighty
Proposed new owners at MediaWorks must be asking whether its second rung TV channel, Four, should continue when the company moves out of receivership.
The channel was beefed up to use some of the surplus content from the Fox deal it negotiated in 2009, which MediaWorks has since tried to wind back.
MediaWorks and its receivers at KordaMentha refuse to talk about the retention of content. Renegotiation of the Fox TV deal is the most significant task as it covers more than half of the content on Four.
A source familiar with the situation suggested that the new owners may be looking at closing Four.
MediaWorks has declined to spell out what role if any Julie Christie - a designated director for the new company - has played in the renegotiating of the contracts.
She told the Herald: "I moved out of content production last year. I chose MediaWorks because I will have the best opportunity to work with management, owners and co-directors whom I greatly respect and who believe in a sustainable, profitable TV business with real vision.
"When it comes to content, management will have our full support as they further extend the company's many successes across all genres."
