It is a pity to see publishing follow other occupations in massive downsizing as a result of advancements in technology and the behavioral changes that came into being as a result.
One reason could be that publications did not see the opportunity to monetize on human behavior and never developed the internal skills to customize content, essentially subcontracting this to third parties sometimes at extremely high exit costs.
I am sufficiently old to remember the days when big companies did not see the little humble hobbyist as a treat, yet if you have millions of humble hobbyists even a small percentage will be able to generate sufficient quality content to challenge the large professional setups.