Still not creative enough. If everybody realizes there's no way to advance because of the old people, everyone will react to that fact. Something will happen. Actually, lots of somethings, with varying levels of success and failure. But there certainly will not be 99.9% of the long-lived human race just sort of sitting around for centuries at a time going "Oh well, guess I'm going to be a loser for the next thousand years."
At that point the crystal ball becomes too fuzzy for me to guess exactly how they will react, except to point out that "go kill all the old people" is a really uncreative solution to the problem, and you've got a lot of people who will be highly incentivized to find another solution, since they plan on being the old people at some point.
A lot of people in the world know that the Kim family is strangling North Korea, but you don't see people rising up to overthrow them. Imagine a world where Kim Il-sung was effectively immortal. Imagine a world where the monarchies of the middle ages could last a thousand years or more. Without something to shake up the status quo every once in awhile the situation tends to stagnate, even if it is a bad situation.
It is possible that human mentality would change if we had to start thinking about longer timescales like this, but that seems optimistic.
>Still not creative enough. If everybody realizes there's no way to advance because of the old people, everyone will react to that fact.
Except everyone (the majority) could be old people too.
If you can live for 5000 years for example, you don't need as many reproduction going on (besides the huge overpopulation that would already be going on).
At that point the crystal ball becomes too fuzzy for me to guess exactly how they will react, except to point out that "go kill all the old people" is a really uncreative solution to the problem, and you've got a lot of people who will be highly incentivized to find another solution, since they plan on being the old people at some point.