In article <bg91jl$lr3$1@spock.usc.edu>,
schillin@spock.usc.edu (John Schilling) wrote:

A billion years is long enough for a technological civilization to grow,
fail to make significant interstellar travel commonplace, fall, rebuild

One of the problems we already face is that we are getting to the point
where we could never recover from a fall because the natural resources
needed to manufacture technology have been degraded to the point where
high levels of technology are needed to extract them.

Also, although I cannot remember the exact timeline of the death of the
solar system, I seem to remember that if we have not emigrated from
the earth in a lot less than a billion years, the expansion of the sun
will have killed us.

It is this last point, rather than population explosion, that means that
a truly successful technological species must emigrate to other stars.
At the moment, I think it much more likely that we will leave it too late,
to when we no longer have the time or resources to do it.

a new and different technological civilization, repeat a hundred times

I repeat that the degradation of natural resources makes it more and more
difficult for each generation to create technology.