Err... You know I often struggle to remember what I posted yesterday, or last week, but children have been conceived, born, started eating solids and learned their alphabet, as well as how to play flappy-bird games on a smart-phone,, since I typed the stuff you are quoting!
Err... really - the average photo isn't taken on digial or mirrorless slr, most are on mobiles - by far. .
Err, this might be a little obtuse, but aren't camera-phones both digital and mirror-less? I presume you mean most contemporary photos aren't taken with a Digital SLR...
The 'cult' of the SLR, is something barely much older than the DSLR (or this thread?) They only really evolved with the common adoption of 35mm 'movie' film, after WWII, exploiting expensive precision manufacture to compensate for the small negative size, which filtered down to the enthusiast market in the 1960's, most often as cheaper, more compact and less compromised range-finders, Not SLR's, which started to gain favor in the 'enthusiast' arena, during the 1970' & 80's, as costs fell.
Throughout that era, 35mm SLR photography wasn't an esoteric state of excellence, and was largely co-coincident with 'casual' photography, most common with 220 or 110 cartridge cameras, or the more discerning casual photographer with a better 35mm range-finder.
Do you really believe that most of the gumpf that comes out of these mobiles at night time because of the marketing says best nightime camera or something is actually good?
It's good that folk have picked up a camera and are taking photo's with them....
Giving them a 'free' camera in a mobile phone they will likely take every where,and encouraging them to take photo's with it making those pictures effectively cost-less, has to be good, compared to the days when 110 compacts sat in draws between summer holidays or family outings, and folk DIDN'T use them trying to 'save' frames on their limited 24 exposure cartridge!
By shear odds, fact that more people are taking more cameras ore places and taking more pictures with them, means that they 'must' be taking more 'better' photos... as well as suggest we should expect as many more complete duffers.. except...... A modern camera-phone has in it's favor an awful lot of electrickery and expert programming, many consumer film cameras of not so long ago, that often didn't even take a battery lacked.
With a micro-sensor, that can deliver mega-pixel resolution, that is in effect focus free thanks to the incredibly short hyper-focal distance of such a short lens, then incredibly sophisticated electronic exposure metering and exposure control, as well as shot by shot variable ISO over a range far wider than the two or three dfferent film speeds you might have been able to buy for an Instamatic film camera, plus a WYSIWYG preview screen offering SLR like through-the-lens composition to avoid parallax error, forgotten lens caps or fingers infront of the taking lens, relatively powerful in built flash, the modern camera-phone offers an awful lot of numpty-proofing to increase the as delivered standard of photos they may take compared to equivalent consumer film cameras.
I may not particularly appreciate the hundreds of farce-broke photo's of beans on toast or Costa coffee cups standing by Big Ben etc etc, b-u-t, in terms of image quality they are usually far 'better' than the tru-print packs of happy snaps passed around in my youth, with 24 pictures in them, 1/4 probably black from being taken with an already used flash-cube, or with half a thumb obscuring the frame, even the better ones showing some curious colour shifts, or blur from hand-holding shake, or or or...
Mention of low-light shots, is co-incident, folk that attempt these more tricky situations with camera-phones may not be getting the best results, but they are getting some! When the 110 cartridge camera was popular, IF they tried anything so challenging they seldom got anything.... so, supporting suggestion, the standards have improved.. something.... even if its no master-piece is better than nothing!
But, the major shift IS that more folk are carrying so many 'better' picture takers, A-N-D taking photo's with them; and irrespective of the technical merits, they are, by both the popularity of the medium and the available display mechanisms, not just taking, but seeing more photo's and being challenged by that to up their own game, whether taking more imaginative photo's or more technically competent ones, the general quality level has improved, in almost all areas.
If I trawled through my archive of film megs,there are horrors galore in my own negs, let alone the shoe-boxes of 110 or 220 negs dumped on me to scan "So we can all see whats on them" by relatives who've put old aunts or uncles in a home! You just never saw the worst of the worst from the film-only-era, as it never got show to any-one! You rarely got to see much of the best, either, stuck in projector carousels, or buried in shoe boxes in the attic, and only if you were lucky stuck in an album in the living room to be pulled out once a decade when Gt Aunt Ethel's god-daughter from Australia popped in because she was told to look you up when she was in the country!
I don't think that digital is inherently any more "disposable" than film, when yes, because of the cost and scarcity so many DID hang on to so many more photos... and as the bequeathed negs suggest, often pretty dire ones! Yet, how many folk of the film-only era can find photo's they took when they were at school, thirty, forty, fifty years ago? How many of the modern age, will in twenty thirty or forty years, possibly not have SD cards or Hard Drive archives of their old photo's but, have them pop up in farce-broke announcements under banners, "Do you remember this from umpety years ago".. crickey I get them now for photo's that I uploaded only last year! A-N-D when I'm dead and burned, that infrastructure of the digi-domain will offer far more contextual 'meaning' or at least explanation of the photo's that are left behind, than the anonymous negs I have been bequeathed, in which I often know not who took them, who is in them, where they were taken, or when, let alone why!
Its an entire push-pull cause and effect sea-change of photo-taking culture, that on the whole, I say HAS seen the general 'standard' of photo's improve, both in execution and expectation.