I've lived for extended periods in various parts of the UK (NI and London), also a small Irish city, and I'm now in Western Australia. All were good places too live (although I wouldn't move back to NI), and comparing prices is very difficult as wages and house prices and petrol vary so much., even within one country, so it really is apples and oranges.
Speaking anecdotally I had an excellent wage when I lived in London in the 90s and early 2000s as I was an accountant, but we thought ourselves lucky to live in a tiny one bedroomed flat, and my commute was a nightmare. Still it was fun, and we were young. I took a huge pay cut to move to Ireland where life was certainly more laid back, but not so culturally stimulating. But we could afford a nice house, especially when my wages increased quite quickly (Ireland was booming). House prices quickly became utterly ridiculous though, and then collapsed, as did the economy. My husband lost his job, and Ireland, beautiful as it is, is bloody expensive on one wage. Also the weather is shit. So we emigrated.
As for Oz, we certainly feel our quality of life has increased a lot, and its not just the weather. We are on fairly average salaries for here, I'm certainly not the high flier I used to be. But we just bought a house with a pool 5 minutes from the beach. We live in an absolutely gorgeous area (that has been on WDU). Our neighbours are tradies, police, nurses etc, yet most of them have boats and jet-skis, several cars and holiday a few times a year. It can get a bit Ramsey Street at times with bbqs etc, but its a much more laid back and positive environment, and certainly a world away from rainy Ireland and bustling London. For us, it has worked out really well. However if we'd moved to Sydney we would have been totally priced out of the market, and life would have been very different!
So, all I can say is, you can't generalise. And its different strokes for different folks. But don't condemn a place because you don't know much about it, and remember Oz is enormous, what is true of one bit certainly wont apply to all, so if you make sweeping generalisations you're going to look a bit daft!