Yes it is stable, inflation is a small steady largely predictable thing, that's what stability is, predictability. By contrast, Bitcoin is highly unstable, no

Yes it is stable, inflation is a small steady largely predictable thing, that's what stability is, predictability. By contrast, Bitcoin is highly unstable, no one has any idea what it's value will be in a week, let alone 30 years down the road, but due to the dollars stability you'll have no problem finding 30 years loans denominated in USD. The USD is the very definition of a stable currency. Stable doesn't mean never losing value, it means being predictable enough to plan for the future.