I have found out what is happening. WordPress does not store permalinks that were previously made. What it does do is guess what link you want by looking at the post name.
Consider:
https://wordpress.com/blog/2021/12/16/new-year-new-success-with-bloganuary/
wget https://wordpress.com/blog/2021/12/16/new-year-new-success-with-bloganuary/
--2021-12-31 00:09:51-- https://wordpress.com/blog/2021/12/16/new-year-new-success-with-bloganuary/
Resolving wordpress.com (wordpress.com)... 192.0.78.17, 192.0.78.9
Connecting to wordpress.com (wordpress.com)|192.0.78.17|:443... connected.
HTTP request sent, awaiting response... 200 OK
All makes sense, but now also:
wget https://wordpress.com/blog/new-year-new-success-with-bloganuary/
--2021-12-31 00:10:19-- https://wordpress.com/blog/new-year-new-success-with-bloganuary/
Resolving wordpress.com (wordpress.com)... 192.0.78.17, 192.0.78.9
Connecting to wordpress.com (wordpress.com)|192.0.78.17|:443... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: https://wordpress.com/blog/2021/12/16/new-year-new-success-with-bloganuary/ [following]
Or:
wget https://wordpress.com/blog/new-year-new-success/
--2021-12-31 00:10:54-- https://wordpress.com/blog/new-year-new-success/
Resolving wordpress.com (wordpress.com)... 192.0.78.17, 192.0.78.9
Connecting to wordpress.com (wordpress.com)|192.0.78.17|:443... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: https://wordpress.com/blog/2021/12/16/new-year-new-success-with-bloganuary/ [following]
--2021-12-31 00:10:55-- https://wordpress.com/blog/2021/12/16/new-year-new-success-with-bloganuary/
Reusing existing connection to wordpress.com:443.
It even works with just one letter although this resolves to different (older) post
wget https://wordpress.com/blog/n
--2021-12-31 00:11:41-- https://wordpress.com/blog/n
Resolving wordpress.com (wordpress.com)... 192.0.78.9, 192.0.78.17
Connecting to wordpress.com (wordpress.com)|192.0.78.9|:443... connected.
HTTP request sent, awaiting response... 301 Moved Permanently
Location: https://wordpress.com/blog/2013/12/03/nablopomo-2013/ [following]
--2021-12-31 00:11:41-- https://wordpress.com/blog/2013/12/03/nablopomo-2013/
Reusing existing connection to wordpress.com:443.
So this is why I cannot find them in the database. They don’t exist there. The solution is to simply pull the old URLs out of archive.org which has preserved them for me.