... I have no clear understanding of what's going on during this 1984-1993 reform period ...
I lived in New Zealand from 1986 to 1992, which included the time where Roger Douglas and David Lange were reforming the economy. It was a fabulous time to be living there.
Prior to the 1980s, New Zealand was a "good" example of a socialist economy. Even the state-provided housing was of very good quality, and virtually no-one was homeless. Employment was high, but so was tax, and import duties were very restrictive. There were some racial tensions, but mostly it was a peaceful and comfortable country.
Although most people had decent housing and a steady job, you couldn't call the country prosperous by any measure. The average person couldn't afford a nice car, because they were extremely expensive. Nor were luxury consumer goods affordable. By that I mean, few people would have been able to afford (for example) a high quality camera. But for sure, all the basics of life were provided for, for most people.
But in the early 1980s, the government had experimented with "big business" capitalism. The government had taxed heavily to fund what they called the "Think Big" programs. These involved very large industrial and "public works" projects, way beyond what the country could afford, and the projects were chosen for political purposes rather than for cost-benefit ratio. Of course much of the profits went to the corporations that contracted with the government to build these things.
As a result of the "Think Big" projects, the government got deep into debt. Inflation rose, and unemployment rose. The Bank of New Zealand was bordering on insolvency.
Against this background, there was a change of government and the Labour Party was elected. Much to everyone's surprise, the Prime Minister (David Lange) and Finance Minister (Roger Douglas) turned out to be a bunch of libertarians and started to tear down the mechanisms of the state. They bailed out the Bank of New Zealand (for almost a thousand million NZ$ if my memory serves me correctly). They deregulated the labour market to reduce unemployment (which worked) and they balanced the budget to stabilize interest rates (which worked), and they moved towards inflation targeting for central bank policy to reduce inflation (which worked).
The were driven by the notion of the government's job being simply to provide a "level playing field" for enterprise to flourish, and to quite a large extent they succeeded. Because government policy was driven by this central idea of the "level playing field", the job of lobbyist virtually disappeared, because there were no favours being given out in response to lobbying.
Lange and Douglas steamrollered ahead, but they went one step further than the electorate was prepared to accept, when they announced the introduction of a flat rate of income tax. They quickly backtracked on this, but nevertheless lost the next election.
Along the way, they had also made three other big changes. They introduced Goods and Services Tax (in a very fair way, without loopholes), but of course in my opinion any tax increase is bad. And they stood up for themselves on matters of principle relating to warfare (even to the extent of upsetting their allies, the USA) -- for example, in the first gulf while everyone else sent combat troops, New Zealand sent a hospital ship. And the government gave the people a chance to choose the voting system. Although the government campaigned to retain the first-past-the-post system, the people chose a preferential system (wisely, in my opinion).