Ned, I have been writing for four decades and I have worked in news for two decades. You are not incorrect in your assessment. I have seen a major decline in writing ability, in writing skills and perceive a loss of personal writing style. Entities also concluded it was a waste of money to employ Copy Editors and simply let the mistakes through now and correct later. This is not across the board, but prevalent to the most popular forms of news.
I also think you get better journalism from a national source. Local print and television media has always been a vehicle for ad sales. In the past though, there was still journalistic integrity. Then, these stations and newspapers learned, if they paid much less, they could still sell their goods. Less pay often leads to less skill. In addition to paying less, they also combine jobs. A TV reporter in the field that wants a job these days better be able to edit their own video, do their own makeup, etc. There are also major players in local news with a proud agenda.
Sinclair Broadcast Group for example directs all of their affiliates what to say and promote with a deeply conservative agenda. They even own more than one local affiliate in some markets. In Pensacola they own the ABC and the NBC affiliate (and two independents). In Bakersfield, FOX and CBS. Flint, they own NBC and FOX. You get the idea. I could go on with several more.
You say people must be dumb, I do not think that is any worse than historically. I think what is different is people want their information quick and clean. Instead of a thoughtful write up that makes you think, it is just easier to be told what to think in a headline or meme. The degradation of news is coming from both sides. The greed and agenda of the provider and the laziness of the viewer. It is a sign that generally we simply no longer care to make the EFFORT. Integrity means taking the time to do what is right. To pay a little more as a consumer or make a little less as a company to do what is right. This is not just in news, but I use it as an example. It could just as easily have been retail. Walmart is cheapest, Amazon most convenient. That is why they are huge despite poor treatment of their workforce. We just say we don’t have time to do better as a society. We should make the time wherever we can.