I'd say that extinct would be a bit of a stretch, however certainly a vast reduction of both technological rate and population is possible through either natural or un-natural means. Populating another planet will increase the chances of our achievements surviving, populating others beyond that will increase it further. Naturally beyond that, the achievements will diverge depending on each planet.
However, if a way is found to generate materials from energy, including food and water, then my outlook on human survival over the next millennia will increase dramatically. There are ways to prevent our demise, asteroid defences, high-rise earthquake proof buildings, but it all costs money...and that is humanities biggest Achilles heel, well, that and the greed that generated the creation of money.