In this particular case, it has absolutely nothing to do with supply and demand.

I was offered a position at the start of of year at a start up. They ended up withdrawing but not because they didn't want me, I have now received a new offer from them (identical to the previous one), but they received some of their funding from a FAANG which demanded that they also apply a 10% headcount cut otherwise they would pull funding.

There is always some amount of churn, and you can manage headcount cuts without laying anyone off.