We were one of these potential bigger customers willing to fork over thousands per month, but the unit cost was still too expensive for us. We tried to negotiate a better bulk rate, but their team was unresponsive and so we eventually went with another service that was more responsive to our needs.  According to the article they only have ~3k paying customers, which means they only care about giant top tier customers willing to pay top dollar.  Seems like a mistake to me, but what I only know from the potential client perspective.