I know that anyone who still raises the spectre of Bob Rae isn't going to have their mind changed by what I'm going to say next (or someone who confuses "polls" with "poles" for that matter) but here goes:
The NDP came in just as a major recession was beginning. That recession, combined with the initial shocks to Ontario's economy due to the CUFTA free trade deal (without the economic shift that occurred since), was awful to the economy. Southwestern and Eastern Ontario were hit hard in the late 1980s and early 1990s by plant closures in places like Belleville, Brockville, Lindsay, Windsor, Chatham, London, and Brantford. Automation of other manufacturing processes (automotive and steel especially) changed things as well, and GM had reduced its footprint in Oshawa and St. Catharines. Most of the last of Toronto's old big manufacturing plants, like Massey-Ferguson and Inglis, closed around this time too. Waterloo isn't yet a major tech hub - and Kitchener also sees some plants close or downsize. The finances take a major hit and there's high unemployment. Any party would have had to deal with that and step back from some of the more ambitious promises.
And the business community is also hostile to the NDP, so they're going to use an NDP government as well as an excuse. The press is also generally Conservative or Liberal friendly, amplifying the blame game.
What the NDP didn't have going for them was business or media support, as well a caucus that was especially under-qualified. There were enough good people to have a competent core cabinet, the talent wasn't that deep beyond that. And then promises were broken, and there were Rae Days, and everyone - including the unions - piled on.
