I actually think the OP's desire for centrist stability and business as usual is a deep expression of denial, and won't be satisfied by any party because it simply contradicts the facts of our historical moment.
Capitalism is failing, all over the world. It is creating obscene levels of inequality which not only hold back the living standards of many, but place ridiculous amounts of economic power - and by extension political power - in the hands of a very few. It is thus entering a stage in which it becomes directly contrary to the demands of democracy.
Automation and AI are rendering human labour obsolete, but we have no plan in place, or even the philosophical basis for one, to deal with what life and society will mean when that's the case. People still sound off about the welfare bill etc. as though full employment is a valid and reasonable goal if individuals only had the work ethic.
Climate change gallops on apace and most countries are falling woefully short of the structural changes they need to make to address it. We're going to have to get used to having less, using less, travelling less. But our metrics of societal "success" are still based on GDP growth so any government that faces up to this reality will automatically be seen as a failure.
People aren't rejecting centrism just because they're bored and want something a bit more fun. They're rejecting it because it no longer works. It's stopped improving most people's lives and it doesn't contain the answers to the challenges we currently face. That shouldn't be so shocking - human society goes through such crises every so often, like when feudalism didn't contain the answers to the challenges posed by industrialisation.
We should be vigorously proposing, scrutinizing and debating alternatives (not least because in the absence of doing so, lazy and dishonest ones will fill the vacuum to serve the interests of the likes of Farage, at everyone else's expense), not pretending we can carry on in a "stable" social and economic order that is patently anything but.