You would imagine that if some big user were slurping up all the spot instances worldwide, then it would level out regional pricing differences. Or, if not level it out, change it based on that users sensitivity to bandwidth costs in/out of each region.
That makes me think that the spot pricing change is a gradual AWS algorithm change instead - I'm sure they'd be smart enough to apply a pricing change with some smooth function based on date.
That happens? I’ve pretty consistently had all spot prices at 30-40% of on-demand.
There were hardware shortages earlier. I think it's just a case of AWS can't expand fast enough to meet demand for now.
edit; and prices tend to surge at end of quarter, regardless of provider. I’ve seen that for years at AWS and it’s only increased year over year.