Extinction in 10 or 20 years would be regarded as being roughly equally bad—since these are small figures smaller than the lifespan of humans and within their planning horizon. So an evolved creature acting in their genetic self-interest can be expected to regard both outcomes as being roughly equally bad.
People don’t act in their genetic self-interest alone, and myself, I’d very much rather die childless in 20 years than die childless in 10 years.