Why Don't Docked Folders Stay Docked?

Yes, same frustration. Maybe they think we just love clicking MacHd > User >user> Pictures> Picture Folder Project > Project folder of Pictures > Pictures to Import folder every single time.. because it's sooo much fun hunting for your folders like needles in a haystack every single time! Hahaha 

I'm a little bewildered why.. seems simple.. maybe it's just too difficult for them.. their white whale.. makes them cry to mommy every time they try hahaha. Oh well, their programs are in so many other ways just so incredibly awesome so what can I really say.. haha enjoy life, appreciate, don't sweat the small stuff! But, hopefully they will...someday so it makes it easier for us not to! haha

Suggestions:

if the import destination is consistent, then it is worth making a named import preset. This comprises all import settings e.g. whether Move / Copy / Add, and "preloads" a standard chosen destination (unless set to Add). Inside this destination there are some options governed by the "Organize" dropdown - a date based system, reflecting the source folders, or "into one folder" which makes no subfolders in its own right. Just above, is an independent option "Into subfolder" where you can define a new sufolder to be created and used for this import batch specifically. All these aspects can be reloaded as a known starting point, on demand, at the bottom of the import screen.

So you can have a standardised workflow whereby you only need to intervene, as to what's unique to each new import. For example, assuming you want to individualise the subfolder for each new Copy or Move import: reselect your import preset to reinitialise the Import settings to a standard known state; enter any particular batch keywording; type in the new subfolder name to be used; click go.

Use of a well-tested import preset gives confidence in what will happen, meaning you don't need to check everything. Multiple import presets can be maintained covering different types of import task. 

On the subject of images remaining on a camera card (that have previously been imported and then afterwards deleted, but now risk becoming unwanted imports a second time) - one way of controlling this is to set the camera to make and use dated folders, or similar provision as available. Then you can be selective so far as the source: in the left hand panel, below the option for selecting an entire card's contents, are options for selecting only a particular folder within that card. Knowing that new desired photos were all taken yesterday (say), you can narrow your import down, to only include that day's photos from the card.

The source DOCK still works.  The TO: folder in the upper right is listed correctly, however the DESTINATION starts at the root, the hard drive, and I must now click to each level - disk/user/lightroom/and so on to find the destination folder.  I like to check it each IMPORT because sometimes I forget to format cards and accidently re-import all the old images I deleted - so they are not caught by "don't import duplicates."  

This function still works on my wife's Mac - I am on 10.15.2 and she stayed on 10.13.

I reported this to Adobe - they seem to think it is a Mac only problem.

My suggestions-

After you have culled out your "keepers"- put them in a permanent folder location (not a temporary one).

Import ALL your "keepers" in one session. Then they will remain in the Catalog Folder view.

Then you also have the option of 'Filtering' the Folders Panel to show only "Favorite Folders". This is by a one-click (+1 more) on the magnifying glass icon of the Folder search panel.

What do you mean Dock a folder? I've been using LR for 11 years and don't ever remember hearing anything about Docking a folder in the import dialog.

Do you mean Selecting, highlighting, a folder?