NavList:

I think that there are two separate issues - Covid and the decline in the use of snail mail.

Last September I purchased a book from the UK through Ebay. I cannot remember the postal details. The book had not arrived by early February and I wrote off the cost as a victim of Covid. At the end of February the book suddenly arrived and I now have all three volumes of the AMN 1938. I just had to be patient.

Snail mail is a different matter. It is in a downward spiral. As the number of letters sent declines services are cut which results in a further decline in letters posted. The standard of service from NZ Post has declined and become so unreliable that I do not think that any sensible  person would send an important decument by NZ Post. If it cannot be sent electronically then a track and trace  courier service would be the safest way to go. Snail mail companies are sunset industries.

Paper is on the way out (old navigation books excepted). For example in NZ the banks no longer (or shortly will no longer) accept cheques. My favourite local radio station used to say "you can contact us on PO Box 123 or text nnnn or email a@b.c."   The PO Box part was dropped  a few years ago and all communication is now electronic.