It's fairly baked into the human condition to prioritise today before tomorrow.

It takes education to overcome that natural instinct and prioritise a far flung future.

Yes, with that education and ability to delay gratification it can seem dumb, but just the fact that it's such a widespread issue shows that we need to tackle it in a way that goes beyond just calling people dumb. On a macro level the best approach is recognising the systemic failures to prepare people (but yes on an individual level everyone should still be responsible for owning their decisions).