I have found this the most frustrating thing. A 'boost' should boost not only that particular story, but also our reader reach and relationship, through the algorithm learning from which readers who discovered us thanks to the boost engaged with our writing (and rewarding our response by giving extra points if they reply to us, we respond, and they reply back or clap for our reply).
When those connections are made, they need to be sustained. Rather than a disposable one-hit-wonder, 'thanks - next!' approach to 'content distribution'.
But that simply doesn't happen. And it's so utterly dumb.
Either they don't want it, because they think that readers would rather have a constant stream of new, different, shiny stuff.
Or they don't know how to code their algorithm to achieve it.
Or perhaps it will be included in a future roll-out of the smarter algorithm they say they're working on.
In which case, I feel they got the boost cart before the new algo horse.