That's one thing I don't much care for in the modern sets. Sure the results look more realistic, but it means that half the pieces are now custom made for the particular set, and often have very little use in a general context. It seems that they've moved from a general building system to more of a per set focused approach.
Then lego seriously addressed this problem and since then have made a large effort to avoid having unique parts in sets. And they were incentivised to do so, because the more unique parts you have, the more money it is going to cost you. Reusing parts is just simply a lot cheaper.
Now there still often are unique parts in a lot of sets, but they are usually unique only in colour or printing.
For example, the current set with the record for the number of unique parts is the Diagon Alley set.
Here is the list of unique parts in the set: https://brickset.com/inventories/75978-1/unique
The thing you will note is that even though there are a lot of parts that only appear in this set, I wouldn't say that these parts are not useful generally. They are mostly just bits of custom lego characters, which you would happily use in any context, or a custom colour for a generally applicable part.
And just looking at others on the site:
https://www.lego.com/en-us/product/lamborghini-sian-fkp-37-4... https://www.lego.com/en-us/product/ford-mustang-shelby-gt500... https://www.lego.com/en-us/product/monster-jam-megalodon-421...
I don't see what all the fuss is about, it doesn't seem either/or to me. The days of off the shelf models having enough general purpose 2x4 or whatever bricks to build totally arbitrary large structures have been gone for at least 30 years, but nothing really seems to be stopping mixing and matching and getting basic blocks for the backbone of a collection. They've just added the existence of $TEXAS display pieces with unique stuff.
I even accidentally got some pieces stuck together in ways that required screwdrivers or pliers to get them out. No big deal!
I would agree though that some specialized pieces are fine. My memories from the early 90s were probably the best balance from my time using Legos. By the mid-late 90s the castle and pirate sets did start moving into imho overly specialized pieces which then lead to the 2000s nadir.
There are also a lot more colors and shades than there used to be, so it is a little harder to make substantial custom constructions that don't look like rainbows.
I do not believe this is true. There are Lego enthusiasts that thoroughly review every new set and are careful to point out the introduction of new pieces and new building techniques. The number of new pieces per set is very low, and even then the pieces are typically well received for the number of new build techniques they may open up.