Indeed, as could I! 
I was notified of this post due to @Speed1994 linking in one of my earlier topics, but that was a discussion that was closed automatically.
Instead, I made a separate Wishlist entry to try to get this better clarified and supported. On the last dev stream, Jayne was kind enough to ask the question from chat, and Martial said he really wasn’t sure - as mentioned in the post above this one. At the very least, I hope we can use the World Hub to ‘exclude’ all of the airport objects for obsolete airfields, such that they disappear from the sim in a fashion… but I’ve not done any airport editing since FSX so not sure if that’s realistic. The ICAO might exist and it will still be on the world map and in every database (e.g. Little Navmap, Neofly) which is read from the sim.
Anyway, here’s a link to the newer Wishlist thread if you’re interested:
Feel free to add your examples to the list. I’m also regularly flying to small airfields, based on automatically suggested routes by external applications. I often find the airfield unsuitable to land on - if I can even find its remnants - due to the age of the airport data. 