Who provides dropboxes actual storage? That provider could just keep squeezing dropbox until the provider creates a copy of dropbox or has them bent over just to the point of them switching to another provider. Maybe dropbox should have been building their own data centers in the mean time, cutting their overhead. That idea of restraining growth in favor of long term stability probably wouldn't sit so well with the shareholders who want their pie tomorrow.
They do have their own storage infrastructure now. It's just a very low margin business and newer entrants like Wasabi are constantly pushing the edge in raw pricing.