Inverted pyramid means that each succeeding generation is smaller than the next. There will be no relief when boomers are gone, because generation Y is even smaller than generation X and there is even less millennials than there is of generation Y.

When you go from 10 active people to 1 retiree to 2 active people to 1 retiree, you can't solve a problem by increasing contributions by a little.

And no, investing money for retirement is absolutely different from spending it on the retirement.