I know less about the age rating bands. Off the top of my head, it's to smooth costs over a lifetime. So it's a wealth transfer from your young self to your old self, if you have typical health care costs over your lifetime: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1361028/
edit: http://www.rwjf.org/content/dam/farm/reports/issue_briefs/20... for more on age banding.
To be clear, I am not saying wealth transfers are bad, but we should be honest about what is happening.
Unless we want to decide as a country to not subsidized healthcare for those that can't afford it and to allow hospitals to refuse treatment without upfront payment... then let's be honest about what's happening there, too. The money comes from somewhere, it's every bit as much of a wealth transfer.
Now, yes, you can argue that it's good to smooth costs over a lifetime ... but that also hits the young very hard when they can least afford it. As does their FICA taxes for Social Security and Medicare.
As we've seen in pretty much every other developed country, this whole welfare state approach is a self-correcting dead end, as enough of the young decide not to play the rigged game and decline to have children.