Oof ye that was incredibly optimistic. Even the lower infra is more expensive than what I pay for lemmy.dbzer0.com.
To get this kind of traffic one needs to be doing similar approach to lemmy.world with likewise promotion from the larger lemmy community, but even than has slowed down. If there were already large reddit communities that they managed, it could help get more people to their instance, but without it, it’s much better to scale upwards as demand appears.