Update: New input from leaker Roland Quandt has been added as he disagrees with the original source's claims.
The Elec's sources say that the Galaxy S24 project within Samsung so far only references two models, code-named DM1 and DM3. One would assume these refer to the basic Galaxy S24 and the Galaxy S24 Ultra, leaving the Galaxy S24 Plus missing in action.
Since the Galaxy S20 in 2020, Samsung's used the regular/Plus/Ultra model types that we see to this day with the Galaxy S22 series, and will likely see again with the Galaxy S23 in a couple of weeks. However, removing the Plus model would theoretically cut the Galaxy S down to just two models: the basic, smaller regular model, and the larger, more expensive Ultra version with high-end features.
It's worth noting however that other leakers don't agree. Roland Quandt of WinFuture says that the DM series refers to "diamond", the Galaxy S23's codename, not the Galaxy S24. Unless Samsung decides to use the same codename two years in a row, it's very likely The Elec's claims of a missing Galaxy S24 Plus don't stand up.
Besides, there's still over a year until we'd expect the Galaxy S24 to arrive, so Samsung would have plenty of time to change its mind if it was considering getting rid of the Plus model. That said, sales for middle models in flagship smartphones are pretty low at the moment, so perhaps Samsung would be making a smart decision to cut its losses.
According to Ice Universe, the Galaxy S22 Plus makes up just 17% of S22 sales, while we've also seen reports that the iPhone 14 Plus, the new mid-range iPhone, isn't selling well either. Users seem to want either entry-level models or the most fully-featured range-toppers, leaving phones like the Galaxy S22 Plus unwanted.
We're likely going to see the Galaxy S23 series debut at the Galaxy Unpacked event taking place on February 1. It should still feature three phones in the line-up, including base, Plus and Ultra models, with new rumored features like the Snapdragon 8 Gen 2 chipset and 200MP main camera for the Galaxy S23 Ultra model likely to take center stage. But even as we start trying out these new phones, we'll be keeping an ear to the ground to see if there's anything more to these rumors of the Galaxy S Plus models' demise.