Spy satellites have been around since the 1960s with very high resolution digital imaging cameras. I just don't believe for one instant that camera manufacturers have not had the capability to produce 16, 20 and 40 megapixel cameras until just recently. The technology has existed for decades. The research and development needed has already been done.
What the camera manufacturers have done is to milk the public mercilessly, producing cameras very slightly better than the one before. 2 megapixels is so close to 3 megapixels that there's very little difference. The same between 3 and 4 and between 4 and 5 and between 6 and 8. As I recall, megapixels came out in the following order...
640k, 1, 1.3, 2, 3,4,5,6,8,10, 14, 16, 18, 20, 24, 36
Each of those steps is infinitesimally small and looks good on paper until you see the real comparisons which are truly pathetic.
3 megapixels is 2048 x 1536
4 megapixels is 2448 x 1632
Notice the truly infinitesimally small change between 3 and 4 megapixels. It's just 400 pixels in width by 98 in height. If that isn't a scam, I don't know what is.
Looking at later cameras we have the 8 to 10 megapixel "leap"
8 megapixels is 3456 x 2304
10 megapixels is 3648 x 2736
It looks bigger but in reality really isn't noticeably. It's just 192 pixels width extra and 432 pixels in height extra.
Really, seriously it has taken camera companies 10 years since the introduction of digital camera to the public to drip a few measly extra pixels each year onto the market? Of course, those few insignificant pixels come at a premium price. Digital cameras started at thousands of dollars and have only now begun to reach the level of cost of a film camera. They're not quite there yet though. In the 1990s I could buy a darned good film SLR for about $200. The cheapest digital SLR is $450. Even allowing for inflation, it's still over priced. And of course the public has been scammed and milked mercilessly.
How many people bought a digital SLR when they first came out and then found the new one was a whopping megapixel extra so dug deep into their pocket and bought the next extra megapixel without realising they weren't buying anything much extra? Sure - they part-funded it by selling their old camera for a fraction of what they paid but they still funded the camera mafia. I would not be surprised to discover that all the camera mafia families were in cahoots and had a cartel in operation since they all released the same megapixel cameras at around the same times.
I just looked at a photo printing chart. As many of my regular readers will know, I opted out of the megapixel bullshit when I bought my first digital SLR which is 8 megapixels. Thus far, I still see no reason at all to "upgrade". The chart states that my 8 megapixels will produce an excellent 20x30 inch print. I have absolutely no intention of printing to greater than 11 x 14 and the vast majority of my images remain in digital and not printed form.
I notice that most camera manufacturers seem to have stopped at about 14 megapixels though they do still try to scam people with ever more megapixels. I don't think anybody is biting any more. I think that as dumb as the general public can be, they have woken up to the fact that they don't need any more megapixels. Most people only ever had 6x4 prints and for those, a 1.3 megapixel camera was more than adequate. They got suckered into buying new digital compacts every year at about $400 a go. I reckon most people got milked of about $5k before they finally realised they didn't need more megapixels. Myself, I had two standards - my compacts were 3 megapixels and my SLRs were 8 megapixels. I have noticed no lack from either standard and continue to operate both standards and will do until the cameras fail. Thus far my sole failure has been my Nikon 3100 which died on me in 2010.
Now let's look at sensor size. I hear various arguments about sensor sizes but as far as I am concerned, they are all a load of baloney. The point of a camera is to take an acceptable photograph. That is the sole purpose of a camera. All cameras now take better photos than was ever possible with film at every iso level. That's from your cellphone upwards.
The major sensor sizes seem to range from very small (cellphone size), small (compact and Pentax Q), half-frame (APS-C) and full frame (24mm x 36mm). The sole difference is that at higher ISO, the larger the sensor, the lower the digital noise. Having said that, the noise levels are pretty low and well managed anyway.
The big downside of digital is the lenses. They have become massive things compared to film lenses. They're a lot lighter. All I can assume there is that they're making them cheaply out of plastic whereas the old lenses were made carefully out of metal and glass. To ensure solidity, they have to put more of the flimsier material into the construction. What we have basically are cheap-ass lenses with a premium price attached. That's without mentioning the inferior optics. The bonus for the camera mafia is that because the image is digital, nobody needs to know how much processing goes into it. Remember the Hubble space telescope that was fitted with a half-assed mirror? They had to write software to repair the damage to each image by the bad mirror. The same kind of thing goes on with digital cameras. The lenses are produced to be as cheap as possible with the flaws all fixed in camera unbeknownst to the user by the camera. This is particularly so with the cameras that don't have optical viewfinders. The camera mafia is continuing to palm people off with sub-standard cameras and optics, bodged to look good with software. The camera mafia is raking in the money and laughing their asses off at the fools that buy the garbage.
Are there any honest camera manufacturers out there that aren't in the camera cartel? I really don't know - I hear so much baloney from corporate sources that it's hard to tell up from down. As far as I can tell, they're a bunch of monkeys.