There's no rush to delete frequencies when the licenses are still active and future use uncertain. From the ECEN listing on the STARNet DB page: "Conventional VHF is still available for fireground or other short range ops."
Quite often old resources in place will be reused for other purposes and leaving the old entries in the DB for awhile allows the chance that someone will hear that use so we can update descriptions to reflect that. The milliseconds lost scanning a few extra frequencies is of no consequence and to those who just can't stomach it that's what favorites lists are for.
It really takes having a local insider to be able to say with certainty that the radios have all been removed and repeaters all turned off and no leftover radios have been donated to the local school/etc to use on talkaround. Sometimes we get that, sometimes not.