In particular, Friendly’s ice cream, which seems to have been the last holdout to put actual pistachios in their pistachio ice cream, has apparently caved, and their “Purely Pistachio Ice Cream” is now “Perfectly Pistachio Almond Ice Cream”.
What other flavors are disappearing, and is it consumer (lack of) demand, or skyrocketing costs of ingredients (due to drought, climate change, diseases, or whatever)?
Neither perfect, nor pistachio. 
I read the ingredients list for the current formulation of that ice cream and there was nary a pistachio to be seen. How is that not an example of bait-and-switch?
I don’t understand the two different “Contains” statements. I suspect the" natural flavors" contains some pistachio something.
Good hypothesis.
Not by Friendly’s, but I miss Butter Brickle ice cream. I see that Blue Bunny makes it, but according to their site, Wegmans, Shaw’s and Market Basket don’t carry it.
Yes, I know there’s plenty of ice cream out there with Heath Bar toffee bits, and I sometimes sprinkle them myself on French Vanilla ice cream to get a “sort-of” Butter Brickle-y flavor, but it’s not the same thing.
On the plus side, Friendly’s seems to still be “ice cream” rather than “frozen dairy dessert”.
Chocolate chip
Pineapple
Bubble gum (with real bubble gum candy mixed in)
My husband’s take on chocolate chips in ice cream is that because they’re frozen, they have no flavor and it’s like eating wax.
Personally, I’d like to experiment with making my own flavors. I was reading in another thread about a poster who received/re-gifted a Cuisinart ice cream machine.
My mind started racing, as Sunshine loves ice cream / sherbet, etc.
The possibilities are endless!!
We’ve got other needs (right now) that take priority, maybe later in the year I’ll save up and get one.
In answer to my own question, maple walnut was a favorite of my family’s in the 1950s in Maine. Was that a regional thing, or it’s just disappeared everywhere over time?
I agree with your husband!
I 
maple walnut!!! My favorite ice cream flavors are
pistachio
maple walnut
butter pecan
Ima nutter 
Maple walnut has always been my favorite (I’m originally from New England), but I now can only rarely find it as Friendly’s, and even then I am afraid they have eliminated most of the maple syrup and almost all of the walnuts. As for “frozen dairy dessert” – actually an artificial concoction of industrial horrors – the stuff is not worth the calories.
Sunshine wanted to chime in on this thread.
Extreme Moose Tracks (Safeway Flavor)
Chocolate Peanut Butter.
Are those her faves, or flavors that are no longer available? Bc I could swear I recently saw a chocolate peanut butter ice cream, but I can’t remember the brand 
I totally agree on all three, and add Friendly’s Chocolate Almond Fudge.
I’ve not had that one, but Tillamook makes a dangerous coffee almond fudge I am also very fond of.
They keep changing the formulation - less peanut butter (chunks) in the Chocolate Peanut Butter ice cream.
And A LOT less chocolate chunks in the Extreme Moose tracks.
In her words “The new formulas aren’t as much fun” – I guess that could be a “shrinkflation” thing.
Well, that sucks. Tillamook has a generous amount of peanut butter in theirs.
As a child I LOVED Thrifty’s (drug store chain) black walnut–kind of weird for a kid!
