I see the "dating" question has already been covered, so I'll add my two-cents' worth. Manufacturers could add all sorts of features at almost no cost by modifying the firmware. They can even add features by means of updates to the firmware. So why don't they? Profit. Even though it would cost nothing to tweak the firmware of the cheapest camera in the line, they save features for more expensive cameras. The prices are higher, so you get more features, and the company makes more money. Generally, speaking, the higher the price, the greater the profit margin. "You pays your money, and you takes your choice."

Different manufacturers have different philosophies as to extra processing features. Nikon is by nature quite conservative in what they include. Burst mode, though, is not something that can easily be done with a DSLR, since the mirror has to move out of the way for each exposure. The same holds true for sweep panoramas, since there would be viewfinder blackout for the whole length of the sweep. Anyway, size has nothing to do with it, since all the functions you mention are firmware, not hardware.

Recently I bought a Panasonic FZ80 for my pending trip. So I have been busy learning its functions and I found it can do a lot more in picture taking and movie capturing than my D610 except detail/clarity/dynamic.
The question is whence the DSLR is a bigger unit, why can't the manufacturer pack those functions such as 4K burst mode, post focus mode, panoramic stitching, multi-focus stacking, live cropping etc. which I think can be achieved by software(firmware). Or the reason is my D610 being too primitive.

I own a D800 and D810, and I do not rely upon "canned" programs or adjustments that they provide - I think they call them "picture controls" - I prefer to tailor and adjust my images to my taste and if I decide to go in a different direction with an image, I can simply create a virtual copy of my raw file without any adjustments and make it the way I want. Once you use a picture control or other built-in image enhancement setting on a jpeg all that data that is not used to create the image is discarded forever - there is no going back.

So, for my photography, I have no use for those "features" you are writing about. Also, the D600/610 is 6 yr old tech. So no, it lacks the innovation the FZ80 has. And what's more, the FZ80 packs 18 mp onto a tiny 1/2.3-inch sensor, compared to the D610's 24 mp on a full size sensor. The individual pixels on the FZ are 1.59µm² compared to the D610's 35.4 µm² - there is no question which one is going to produce better images in low light with high ISO. Comparing the two is like comparing a Bugatti Chiron ($2.5M, 15 mpg to 35 mpg) to a Toyota Prius Prime ($30K, 133 mpg) and panning the Bugatti because it only seats 2 people, has no room for luggage, and doesn't include a JBL based entertainment system with integrated GPS, remote climate control, SafeSense collision avoidance with pedestrian detection, blind spot monitor, backup camera, satellite radio, dynamic radar-based cruise control, lane departure alert with steering assist, and fully automatic headlights, high beams and windshield wipers.

Each car fits a certain set of widely different expectations - same goes for cameras.

I hope this isn't taken wrongly.
My 610 is an incredible camera and if and when I ever learn how to take a photograph it will serve me more than well.

Whenever I feel frustrated by a camera and its inability (or is it mine?), I look at the picture that really hits me as being a really good picture that shows wonder and movement and setting and life and ... it was taken on some sort of pinhole thingy. I wish I could take as good a picture as this.
I look at this and want to go there, talk to that boy who is cleaning shoes, chat to the man whose shoes are being cleaned, look at the trees and ....

So maybe get a camera that takes pictures and think about the picture and the memory and the event and stop worrying about all the fancy whoo haaa thingy stuff.

Sorry, I'll go away and be quiet again.

Don't waste money on fancy cameras!!!

Different manufacturers have different philosophies as to extra processing features. Nikon is by nature quite conservative in what they include. Burst mode, though, is not something that can easily be done with a DSLR, since the mirror has to move out of the way for each exposure. The same holds true for sweep panoramas, since there would be viewfinder blackout for the whole length of the sweep. Anyway, size has nothing to do with it, since all the functions you mention are firmware, not hardware.