I don't have any data on this, but it's my hunch about why there's so much economic resentment these days.
Depends if they work in a unionized industry.
"If you break your arm, what percentage of your income will be consumed by medical costs?"
In most industrial countries, including the US after the ACA, very little, because of health insurance.
"there's so much economic resentment these days."
That's inequality. When everyone around you is poor, except for a few rich folks you don't see often, it's not as big a deal. When you're constantly exposed to the things you don't/can't have, that can lead to resentment.
This goes back to your first sentence: "Although almost everyone is better off in material terms than they were two generations ago, I fear that the level of wealth required to live a "comfortable" life may have outpaced that increase."
In the US, Median Income peaked in the 1970's and has been flat. https://en.wikipedia.org/wiki/Household_income_in_the_United...
The poor (in the U.S. anyway) are relatively worse off than they were 2 generations ago - the bottom 50% have seen very little growth in income in 50 years, while the top 50% have grown a lot more. http://www.russellsage.org/sites/all/files/chartbook/Income%...
Not all countries are as bad as the US, particularly Canada or Europe, because they have strong redistribution systems (health and social insurance, etc.). But the trends aren't great.
Not if all your resources are sucked by insane rent / housing prices.
Work has never been easier in the US than it currently is. Record number of office workers, minimal number of farmers, factory workers, and manual labor in general.
Several years ago I worked on a farm for a few months helping out a relative. It was exhausting work, but I found it much easier than some of the programming work I do as a living.
If you're ok getting about the minimal wage for some gardening, or house cleaning, or trash removal, you probably have good chances (e.g. you'll outcompete an illegal Mexican immigrant by just knowing the language well).
Machines increasingly obviate jobs that don't require qualification. On one hand it is nice because humans need to do less and less dirty, mind-numbing jobs. OTOH being a traveling beatnik sucks more and more.
I'm a huge fan of "Your Money or Your Life" and by extension the Financial Integrity program, which advocates for people to rethink their relationship with money as well teaches people how to make income regardless of employment status.
What I don't think works so well is teaching everyone to be good at money management. Ignoring the other possible contributors to being very poor (culture, prejudice, whatever), there is undeniably a component due to intelligence. We should thus expect some portion of these very poor to be incapable of managing money, no matter how much they have, and a better policy would be to manage their money for them. This already happens for some mental hospital patients that are out in the real world but need support for medication and housing and food, and if you give them too much unrestricted money instead they'll just buy a PS4 or something else that's shiny and the money will be gone, they'll have to sell their PS4 in a few months to keep paying the rent, and then a while later they'll be evicted due to non-payment. Better to give them a smaller amount of unrestricted money on top of the other aid, but in my experience the same spending patterns emerge (that is, spending it all), very few save, or save beyond what is necessary for a particular shiny toy. There is also a disincentive from getting a job that pays too much income, because their benefits are based on income-received and can be taken away very quickly, but that's another issue. My point is that such individuality-invading money-management could probably be beneficial for more than just the mentally ill, but it will be immediately dismissed by people intelligent enough to manage their own money and who wouldn't be affected by this as nanny-statism.
As for the people in the poor countries, they're getting richer because of this process, to an extent that the capitalists have to move their cheap labour manufacturing further and further - just see the trends in textile, for example. So it's all levelling, I would not worry about this particular aspect.
It will happen over time. Levelling is an unavoidable consequence of the globalisation.
> new types of software-enabled currency and exchange
Yes, this can be quite a game changer, may even remove the banks from the picture entirely, but, again, it all will need time.