I was recently talking with a prominent guy from one of the social services councils about this (I unfortunately cannot go into more detail lest people actually figure out who this man is). My country Is currently opening itself up quite liberally to international trade especially with Asia and exporting/importing that has brought
insane benefits to our access to consumer goods (Australia's cost of living is high due to a multitude of factors, but geographical isolation and previously strict trade protectionism factored in significantly), however it has meant our manufacturing sector has significantly reduced.
He mentioned that our opening to trade has increased the mobility of income quite dramatically - how? Because we are currently riding out a 'mining boom' and exporting raw materials which require a huge amount of labor to get out of the ground, and these materials are in high demand, so people are willing to pay well to anyone who is willing and capable of working out there. But with it, he noted, the life cycles of incomes have shortened - how much has the 'life cycle' of an income shortened? To about a decade.
See the thing is, previously people would dis-save in early years while they study, get jobs, enter an industry and then save across the course of their lifetimes - that fabled 'nest egg' baby boomers talk about. Then, when they retire and leave the workforce, dis-save again. Now, however, people are instead getting jobs and rocketing to a remarkably high income within a few years, then when the economy's structure changes, finding themselves without work. That in itself is not a problem if the industry did not run dry - but mines become barroscas, and China's economy is slowing down. This kind of unemployment is called structural unemployment (as opposed to cyclical unemployment), and is supposed to be filled as technology and economic conditions open new opportunities, however the global economy means that it is no longer sufficient for technology and economic change to open jobs; labor is not so mobile many people can take up the new mining opportunity in South America, say.
I think one of the core tie ins with income mobility is now that the life cycle of working and careers has changed - they are no longer certainties, and economies in general are very very ill equipped to deal with structural unemployment.
@yawning sneasel is talking about the way that most industries are trying to make labor more flexible - through education and upskilling, which is not necessarily a poor form of policy, but in America and (to a lesser extent) the UK, College is prohibitively expensive and has lost much of its value, however in my opinion, to prevent further stratafication, there needs to be new changes to the manner people can trade their labor internationally. Globalisation is not a bad thing, but it is harmful when social and structural policy means we cannot chase that new mine in SA, people cannot take up opportunities that are located elsewhere.
So, my suggestion would actually be that to help people maintain their ability to capitalize on opportunities, several things need to happen globally. A universal language that is taught to a competent degree, education reform to allow equitable access to individuals, and finally, if trade barriers are lessening, immigration barriers need to lessen as well.
I'll quit my sperging, but there you go, that's an outside opinion.
