Problem with the extra features / functionality being built-in is that they aren't as good as a dedicated piece of hardware for a given function.
True and everyone has differing expectations.
So a buyer might think:
Will it work well enough to suit my needs and I then not need to buy another piece of equipment ?
Also you may require to be able to use both or more functions at the same time which I don't believe is possible with a DSO?
Off the cuff there's 4 examples that come to mind.
DSO's with MSO (LA) capability.
Split screen FFT mode.
Decode.
Inbuilt AWG.
All were once the domain of dedicated instruments but are now available in several basic entry level DSO's.
We'll see more of it I'm sure until a manufacturer spots a marketing opportunity to offer a good bare bones basic DSO and then the clock starts at zero again.

Also if the DSO fails, then you are also bereft of the other pieces of gear that it attempts to simulate, that in my book is just a no no. No audio phile would accept a all in one unit for the same reasons.

We used to say that about a car with electronic ignition, then EFI, ABS, Cruise control, Climate control, Auto locking, ..............
I believe it has become nothing more than a cynical means of justifying the higher starting price as you mentioned, factoring it in, the cost is not bad, looks like an attempt to minimise the higher then it needs to be price.
Of course...................or requests from customers to add functionality.
C'mon, how can this be a bad thing for anyone getting into the industry ?
Fact is, it suffers from the constraints I outlined above and also of course many people will already have the various items already in their home labs.
Sure but many don't, they really don't. I've acquired a bit of gear over the years but for those decades younger than us they haven't had to opportunities to gather what we have. Please understand and accept that.
I doubt it costs that much to add in these mediocre extra functions anyway as with digital systems, most of the hardware is already there and is more software driven to make the changes?
Developing software features costs time, effort and money too. I know the hardware crowd tends to underestimate that, but if you just look at the horrible software that's consistently supplied with even very expensive logic analysers you know that proper software development isn't trivial.
You nailed that one.