I'm also a long-time Note fan, dating back to the Note 3. While the Note is known for top-end specs and large, glorious displays, the defining feature of the line is the S Pen and its suite of tools that are unique in the industry. Everything else might use a stylus... but the S Pen's features make difficult tasks much easier.
I need the S Pen: not because I can control my music with it (but I can and I do); not because I can use it as a remote shutter for the camera (although I routinely do that). I need it because my fingers have a rebellious spirit and don't go where I want them to. Their favorite prank on me is typographical errors - hitting the wrong letter as often as possible to slow me down and extract some fine Navy vocabulary from me. The S Pen allows me to type, tap and swipe with surgical precision, speeding up my work considerably. It's even faster than voice texting with the keyboard taking dictation, as the keyboard will often insert the most ludicrous things even though I'm speaking slowly and clearly.
With the lines blurring between the Galaxy S and Note lines, though, the only real difference left is the S Pen. Galaxy S devices are just as big, just as bright, equally powerful for everyday tasks... and the Note gets the same cameras as that year's S model. It makes sense, then, to merge the Galaxy S and Note lines and use the Note's engineering resources to make a single device so much better.
Now, let's add the S Pen to the Z Fold 3! If Samsung can build that device with a decent aspect ratio instead of long, skinny screens, the possibilities are endless! Artists will have a huge canvas on which to work; Maps will show entire cities, and we can use the S Pen to mark destinations and routes; power users can jot notes at meetings with a massive screen, which means less scrolling. Engineers and technicians can create flow charts and diagrams, or even write complex equations that the phone's processor can read and solve on the fly.
The Galaxy Note has pushed the boundaries of the smartphone industry for a decade. Initially mocked and ridiculed by the usual suspects, it has earned the respect of everyone in the tech blogosphere (yes, even Apple fans). But there's really no reason to keep a distinct line when the Note's unique S Pen features could be so much more versatile in the S and Z Fold lines.
For me, it's not the death of the Note... it's the Note's natural evolution to bigger and better things. My 2¢