I feel like this should be public. I wonder what would be the repercussion of a gofundme to buy it once and make it publicly available. There aren't many downsides of updating every couple years.
There are plenty of 'good enough' options that are free; just ignore the USPS' offerings unless you ABSOLUTELY have to match them 1:1 for business reasons.
https://postalpro.usps.com/ZCB_License would seem to prevent such a use/distribution of the data.