What Is Your "End Goal" With Collecting?

I'll say mine. I want a complete collection of US coins Capped Bust - Date. All dates and mint marks excluding ultra rarities and gold. Ambitious? Yes. Possible, 100%.

I have a lot of sets I'm working on. If I had to chose one, I'd probably say to get one of every German state.

It's highly unlikely that I even have 20 years left (I will turn 80 this year).
I have no end goal.
I just want to continue collecting.

My Type Set is two coins short of completion but I won't be able to get either.
Both are mid 5-figure coins.
I use the NGC Registry Set definition of a Type Set (1793-1964).

My current interest is early copper.
That will keep me busy until the end.
My wife knows who to contact to handle the sale of whatever coins I have when they slab me.

I'll probably make it 20 more years, 30 is also possible and if I live as long as my grandmother I can make it to 40 years, but 50 gets hard (I exercise everyday but I still like wine and espresso)

So what is my final goal.

Let's see, I have a few goals. I want to complete my US Currency type set. I still need a few fractional currency.

I want to complete the American Innovation Dollar series.

The 7070 that I started and the IHC

And after that? Probably go back to astrophotography. I don't stay in any hobby after I complete my goals. So as of now my goals probably go out 5 years.

At 21 I've certainly got a lot of time ahead of me to rethink my end goal. However, at the moment it is to finish the sets I've started:

US Classic Commemorative Type
Dansco 7070 (with Gold Page some day)
Custom Dansco 7070 (Draped Silver - date)

and then to:
Create a "1 box collection" (this is an idea I heard once that's a single box of 20ish slabbed coins. When you want a new one, one has to go. That builds up overtime to make a super awesome set of 20ish, I keep it pretty minimal on the excess bulk that I collect so this idea really grabbed me)

and then of course continue to upgrade... meaning there never truly is an 'end'

Don't bother getting slabbed, you will probably get a details grade .
I have no end goal, the hobby is what I do to pass/fill the time because I enjoy it.
John1

If money were never an issue, my end goal would be the rebuild Dr Norman Jacobs Korean coin collection. He built the most completely Japanese and Korean coin collection of modern coinage (1800s~early 1900s) in the world during his time in Japan/Korea in the 40s or 50s. I already own on piece of his collection and want to rebuild it over time.

Realistically, I might collect 10 more years, then start selling off my collection.

I have several themes I enjoy, only two of which really have well-defined "end goals":
1. Complete a modified Kingdom of Poland OFEY 1507-1795 (modified in the sense that I am eliminating a small number of years where no coin can be had for under $1,000). I have all dates in the 1500s, missing 3 dates in the 1600s, and more like a dozen in the 1700s
2. Complete an OFEY back to 1474 and in the gaps of the Poland OFEY 1507-1795 using only Duchy of Brabant/Flanders, Duchy of Lorraine, near-Poland states (Silesia, Pomerania), and saints. As is the case with @pepactonius, I have some tough dates in the 1400s, then 1506 a handful in the 1600s, and another handful in the 1700s.

My medieval (pre-1500) OFER for Poland, Brabant and Lorraine has looser goals, in that I have more than one type for some reigns, but have gaps for other reigns that I hope to eventually fill. And I have a few more specific saints I would like for my saints collection, but this one could easily double from the size it is now with the many obscure saints of the Italian peninsula and central Europe. So these areas will probably never have "end goals."