Opinions etc, but I'd argue a functioning economy was when any full time job could pay for a house and a family.
Ignoring the "OMG my McDonalds job should fund a McMansion" aspect of that which some sometimes float (those are jobs for teenagers, I will take trades and semi skilled on up for this) then give or take for about 5 minutes after world war 2 in the US when it became the factory of the world owing to Europe being rubble (continuing on with a bit of boom in some aspects, aka not the little guy, owing to the rest of the world paying a tithe thanks to petrodollar, and then them giving credit cards to the useless masses, the productivity-compensation curve having 1973 as a clear turning point), and maybe the five minutes between the then modern apprenticeships and before industry left the UK a few decades later, both of which were illusory at best and more likely an actually valid economic use of transient... all seems like nostalgia for an age that never existed.
1930s were not good anywhere, 1920s was an illusion (it led to the crash that caused the 1930s), world war 1 before that which also led to voting rights if you want to go that way, Victorian times were hardly the pinnacle of good living (not to mention your wife and kids were probably in the factory as well to afford the hovel), pre industrial revolution you still all worked on farms (so awful it along with automation caused the rise of cities, US doing a bit of manifest destiny to pad it out) and then we are back to rebelling against a feudal lord because taxes to fund a foreign war were too high every few decades and outright serfdom before then (maybe with the occasional blip following a plague that reduced the workforce such that demand outstripped supply for a decade). Australia had a marginally different timeline but still broadly similar to both of those, Japan stagnated/went for ballooning debt after its little economic miracle, bit of western Germany owing to being propped up in a propaganda effort for the cold war...