If anything, the shortcuts that digital photographers take degrade the quality of the image. The tiny image circle of DSLR lenses means that you can't control the image at the time of exposure, and have to use information-destroying transforms in post-processing. In the end, it doesn't matter, art is art, and jacking up all the colors to a million gets you the likes on 500px. Nobody will notice that the lighting was poor or that some of your square-at-the-time-of-exposure pixels are now rectangles. (That's why everything in the grocery store contains sugar. Nobody ever complaints about too much color, and nobody ever complains about too much sugar. It's a great way to make something mediocre delicious for the mass market!) But there is some value in getting it right in-camera, if only for the sense of achievement.
Nanoparticle films are coming out. Gigapixel resolution in 35mm format.
The laws of physics most certainly are THE fundamental thing in the way. Electron leakage, current ripples at nanoscale, capacitive interference. There's a lot more involved when it comes to semiconductor technology.
Digital has beaten 135 film, but it still hasn't beaten 120 / medium format in several key areas. I would be surprised if digital beat 4x5 in the next 10 years because there's no substantial market for such a product.
Basically, DSLRs require perfect conditions in the field to actually achieve the sharpness stated by the camera manufacturer. A 4x5 sensor allows much more slop.
Analog film has far higher dynamic range than any digital format. The camera itself makes no difference with all the f-stops, the analog domain is far finer-grained. Film is not effected by moire.
High end digital cameras have better dynamic range than most film cameras. Eg. check out this Nikon D810 photo of a cloud lit by lightning: https://www.dpreview.com/files/p/articles/7705642292/DSC_481... (source: https://www.dpreview.com/reviews/nikon-d810/14 ). Maybe a large format camera could capture something like this but it would definitely be impossible with 35mm.
I spent years struggling with high dynamic range/contrast acutance with severe weather photography and digital cameras. Blown highlights, color noise in shadows, rough tonality through contrast transitions, etc. Specific films (not slide film like Ektachrome) were my salvation.
Also, noise is not the same as grain. If the difference is unimportant, I'd think the other nuances relevant to this conversation may be as well.
I consider grain to be noise, just like vinyl surface noise is noise. I don't consider any distinctive and "artistic" defect of a reproduction medium to be a good thing.
Grain = resolution. Do you consider your 72DPI monitor to be noisy?
And that's not impossible with 35mm at all. Chemistry advances as well, you know. The age of nanotechnology. We're getting analog films in 35mm format that do gigapixel+ resolution equivalent images. Along with that, these newer chemicals are far less susceptible to noise. Add to that things like high refractive index lenses made from fluorite and optical calcite, and analog cameras can still hold up to/stomp digital, all day. I do keep my eye on the analog world of film, because I've got ~$10K in equipment sitting in my bag and I like having equipment that I can use.