I have nothing to disagree with your opinion. But the digital data of the sample images are literally the direct result of the test of the cameras, which was impossible with the printed matters in the film era.
In addition, the purpose of reviews of digital cameras and lenses are different from that of photo books or literature: they are mostly there to help people decide if a camera would suit their needs, whether it is the latest model or older model as a used camera.
Even recently, I bought several photo books of the photographers I like. But I had stopped buying camera magazines for the reviews of new products since I had switched to digital.
Right, I understand that online there is a wealth of data on equipment that cannot be found in print. However, the question of how to make it profitable (or at least to pay the bills) to offer this content has not been answered. As long as some free content is available, people will not pay for that type of content, and then the material will be lost once the companies or people who offered the service realize they can't continue to offer it when there is a financial downturn in the world's economy.
It's kind of the same with newspapers. When the web appeared, major newspapers started to offer a lot of free content, apparently hoping that it would eventually become profitable, thinking that they must be there to stay relevant. Then they started cutting costs and laying off people even though they had more work to do (i.e. both print and online reporting & photographs, and video) than before. This is probably because many people like to get free content and see no reason to pay for what they had to pay for in the past. How, then to make it possible for people to work on serious content as a profession? Now "content creation" is a term used for basically what is advertising for products, and often lacking substance.
In my opinion, it is the offering of the free content so widely that creates the long-term problem. If the public had not been given so much free content (which is paid for someone, either in free time, in the equipment used in generating it, or by taxpayers in the providing of the internet's infrastructure) they'd be more willing to pay for quality content today, and we wouldn't have to worry about what will eventually be lost. I remember when the web was new, people said that content will never disappear, but a lot of online articles I cannot find any more.
I don't mean that people who are altruistic and want to help the community should not have published free reviews etc. It's highly valuable (much more so than magazine reviews in many cases, which were highly variable in quality). Together the online forums create a breadth of knowledge that wouldn't exist without the internet. But the question of how to solve the monetisation problem is still there in the long term. It doesn't seem like the highest-quality content and financial rewards go always together. It might be that sites with a low signal-to-noise ratio are busy with brand wars and yet manage to stay afloat, while forums with quiet and polite members might not.