There is an episode of the original Star Trek, called All Our Yesterdays, in which people who lived on a mostly cloudy world did not figure out space travel until it was too late to save themselves from their sun, about to go supernova.
However, they *had* figured out time travel, so their solution to their predicament was to send their entire population back to earlier ages of their planet, after adapting them to live in those earlier times, so they would fit in. As a plot device this was necessary, that unless their minds were modified they would die; or else they could alter their past so that they did develop space travel.
Since significant space travel is so difficult, and the distances involved so great, this impresses me as a not unreasonable solution.
Mr Atoz and the Atavachron...