There are no stupid questions about this. At the very end, the doc says some stuff about what happens with this virus long term. The detail I picked out is that all the viruses, including all the variants of the common cold, become weaker with time, and simply enter the rotation of viruses we already have anti-bodies to, and if you do get it, it will be no more severe than the average cold.
This particular one is just new, so NO ONE has immunity yet (well, some do now....) and it’s a bit of a nasty one, spreads easily (no kidding), and it’s killing lots of folks. So until we control it short term (distancing, wash hands, NTDF (no toucha da face)), a vaccine finally gets distributed, and enough time passes, the danger persists.
As to origin, good luck ever learning the truth about that one. Viruses have been coming to reality for a long time with no Intentional human interference. The whole mutation thing. New ones pop up all the time. Very few get out into the general population the way this one did. Hopefully we are learning what to do (And not do) next time.