Been collecting about 4 or 5 years. Have a large percentage of Napa Cab but given that everything now seems to be getting in that $300+ price range I’m feeling the need to cut back on my napa cab lists/buys. This is what i currently buy
Promontory
Colgin
Lokoya
Myriad
Rivers-Marie
Carte Blanche
Kinsman Eades
Macdonald
Roy Piper
Impensata
scarecrow
Maybach
Memento Mori
Vida Valiente
Realm
Bevan
William-Mary
Ummm, I’ll take your MacDonald?
Easiest way to figure out if you should stay on the list-
If it will cost you more in the secondary market to buy it, stay on the list.
If it will cost you less to buy it in the secondary market, drop it.
what Ian said
If you collect to drink instead of as an investment, which wines rise to the top for your drinking enjoyment? I dropped collecting some of the wines you list because after tasting a few vintages, their taste profile just didn’t line up with my palate.
A lot of subjective calls to be made in there, but I would definitely keep Kinsman and MacDonald no matter what. As to the rest, depends on how much you enjoy them and how deep your current inventory is. Some of those can be had in the secondary market at or even below release/mailing list price, too, and those ones are lists I’ve dropped off of recently.
I was on many of the same and have cut your list down to the following. Outside of Kinsman Eades, I’ve been focusing on more mid-tier (relative to Napa) price point. And I’m still waiting for Macdonald.
Rivers-Marie
Kinsman Eades
Roy Piper
Maybach
Realm
William-Mary
I’d add DiCo for something a little different.
Similar trajectory here. I started joining lists 2-3 years before you, and was up to a similar amount of lists. In the last two years I’ve dropped most and I am down to seven. One thing I looked at was multiple lists I was on that had the same winemaker and picked the one that I enjoyed the most to keep. And which ones give me the pleasure when I open a bottle, not necessarily the ones that get the most attention on this board.
That was my first thought too!
I am in the same boat - palate has begun to move away from region a bit (my wife’s hasn’t though!) so I find myself drinking less of it, and it just gets harder for me to justify the price point of entry anymore when there is so much great wine being produced for much less elsewhere. My thought process is similar to Ian’s in that if you can source in secondary for cheaper, why lock yourself into an annual purchase habit for the list if easy to source and for potentially cheaper? I would not drop the likes of MACDONALD, Kinsman, or Roy Piper, personally speaking. And those, I say that out of personal enjoyment as I find them truly distinctive and there is a definite scarcity to them - not to mention the personal connection in that I love visiting, want to support them as people, etc.
If you have 4-5 years of accumulated Napa cabs. my question would be, “how much more do you need?”
If it’s all you drink, then perhaps other’s advice here is on point.
If it isn’t all you drink, maybe it’s time to buy other wines you enjoy.
You’ll still have a nice stash to enjoy over the coming years.
I’d review your drinking history. Buy the ones you actually drink and look forward to opening. If they don’t excite you then drop them.
Agree with others regarding replacement cost calculation but would be less fixated on this.
First question - are you cutting back because of price? Because of duplication? Because you’re not drinking them enough?
And what do you want to replace with? Or are you just going to purchase less altogether?
I think Ian’s commments are spot on - assuming you are looking at this from a cost rather than enjoyment level…
Cheers
I’ve been cutting back on modern Napa Cab lists lately for the following reasons: (1) they don’t excite me as much as the used to, (2) I’m not sure how well a lot of them will age over the long term, and (3) most importantly, as the current prices, along with shipping costs, go up and up, I can get back vintages of the same of fairly similar wines for less money at auction.
Similar situation and have aggressively cut lists over the last few years. If you end up with 2-3 cases of Napa / year, depending on how much age you like, you’re sitting on hundreds of bottles that aren’t ready to drink.
I look forward to opening and have thoroughly enjoyed every bottle of Rivers-Marie, Roy Piper, and William & Mary. I can only imagine I’d feel the same way about Macdonald should I ever get an allocation. These producers, for me, represent exceptional value as the quality (high), wine profile (hits my palate the right way), and costs are fair.
I agree with how others are looking at it - if you can find what you want at retail at similar to list release prices, being on the list is less important and gives you greater flexibility.
Fwiw, I have a really hard time going over $200 for a bottle of wine. I have and do, but your line in the sand may vary. There’s so much good wine below that number and I rarely find myself blown away above it.
If you like the wine and want to continue enjoying it with friends and family, stay on the list.
It really is simple. 
I agree with Jim’s remark above. I own and thus purchased a lot of those you mention, and some others, Bella Oak, that you do not. But since I am not a flipper, I don’t seen any point staying on these lists for an extended period. But that may be because I drank a lot other sorts of wine. (It does slightly annoy me how the folks at the wineries expect you to buy forever, though it is also of course wholly understandable.)
No one would ever cut Macdonald (unless you were dead).
Drop everything except for MacDonald and start buying old world wines 
If you drop off the MacDonald list that will bring me from 1502 to 1501 on the waiting list and THAT is pretty exciting!