Large piles tend to get larger, that's the major issue.
It's easy to be a monday morning quarterback about management. Even so, no company is immune from blatant mismanagement. It's not a no-brainer to effectively manage a large corporation, not remotely.
For an example, look at Apple in the 1990s. A series of CEOs were all unable to get the company moving again, until Jobs was asked to return. (And those CEOs were all experienced and well-educated businessmen.)
Microsoft couldn't kill/buy Google, Walmart can't kill/buy Amazon. Microsoft and Walmart are still big, but not that powerful anymore.
So while i think they can buy their would be destroyers, that is actually very hard, because they mostly only realize that too late, or are stopped by something else (Microsoft did buy shares of Facebook before Google).
Where is Commodore now? DEC? SGI? Intergraph?
From 1955 to 2016 only 12% of firms remain in the Fortune 500. It's not clear that this sort of churn isn't still happening:
http://www.aei.org/publication/fortune-500-firms-1955-v-2016...
However, it's also worth noting that no churn would take a long time to show up.
I used to have a chart which showed the top 10 corporations by market cap, decade by decade. You didn't have to go very far back before you didn't even recognize the company names.
I'm old enough to remember all the fear IBM struck into the hearts of everyone in the computer biz in the 1980s, fear that seems so laughable now it's hard to even remember it.
Same thing in the 1990s, but with Microsoft.
Other companies that inspired fear and certainty they'd take over the world - HP, AT&T, RCA. RCA? Anybody even recall that RCA was the name of a company, and not just the plug ends on your stereo equipment?
Anyone remember that old WKRP episode where they were making fun of the fear of "The Phone Company", i.e. AT&T?
There's a good reason for the decline of large corporations - they get too bureaucratic and complicated to manage efficiently. They tend to accumulate too much entrenched interest in obsolete models and technology. I.e. the world passes them by.
But in fact we have seen a lot of consolidation in the photographic industry. Back in the days of film everyone had to choose from a select few manufactures of chemical film. but people who created photography had a wide variety of equipment manufacturers to choose from, and those who did it professionally had a wide variety of sales channels into which to sell what they produced. Good photography was valuable and many thousands of people could support themselves as freelance photographers.
Now we still have a decent set of SLR vendors. There's Nikon, Canon, Sony. Um, probably some Chinese manufacturers. The point and shoot market has been eclipsed by the camera phone, for which there are now exactly two platform providers.
But the collapse in price of photographs also produced a collapse in value of photography. All those freelancers found their sales channels dry up. There wasn't Look or Life or Nat Geo or hundreds of other publishers who needed photographs and were willing to pay top dollar for excellent work. Instead photographers found themselves trying to sell the rights for pennies on a few photo agency platforms, or more likely surviving entirely on event work.
The choke point at film manufacturing went away for sure, but we have a new choke point at the publishing and delivery end, and this choke point exerts vastly more control over the entire industry than the film duopoly ever did.
https://www.reddit.com/r/pics/
There's a long list of such platforms anyone can upload pictures to. Or they can make their own websites. Anyone can do this.
Sorry, I don't see any "choke point".
How many such platforms can you name? How many such platforms would a typical member of the public be able to name? What is the distribution of traffic across such sites? (Hint: Zipf's Law applies.)
Why is it that the information / comms world continuously, since at least the early 20th century, seems to settle on a single dominant provider, or at best, a handful of leading contenders within a field? Telegraph, telephones, television, computer equipment, computer languages, operating systems, social networks, "Web portals", etc., etc.