antibodies only last for a couple of months they say now
However, memory T-cells typically last much longer, which means that if you are re-exposed to the virus at a later date, you manufacture antibodies straight away. They tested some of the people who had SARS 17 years later - most of them still had T-cells. This virus is very similar.
and a vaccine won’t offer meaningfully lasting protection
There is, literally, no evidence for this. We haven’t got a vaccine yet, so we can not possibly know how long it will provide protection for. In fact, we won’t know until we’ve given it to loads of people and watched them to see how long the immunity lasts - I would imagine that is part of the trial protocol. However, the scientists working on it - the ones who actually understand all this stuff, expect it to confer useful protection of 1-3 years.
If it’s only for one year... then you have an annual jab, like millions of us already do for flu. Big deal.