Reseller, your observations are so important, and so correct.
What is scary to me is that the more big brands have the deepest pockets to pursue multiple domains, get them ranked, put money into them, and make them look pretty. But, often times, it is simply regurgitated information only packaged slightly differently.
Another technique that I am seeing is that some of these big companies that own multiple domains, taking many of the top spots, also "lease' many of the other sites. Basically put, they'll put ads that look identical to adsense, but in fact, those adds all redirect back to the big-money sites that also own many of the other domains in the niche. The top ranked site in my niche does this - every ad click and phone call goes to the big company.
The big-money site/company can afford to outbid adsense, and pay more for a click if they replace adsense with identical-looking ad blocks.
Within some of these multiple domains, there are even more techniques happening that I think help the site, and page, but are a disservice to the user. Taking your example of 'assisted living' someone searching for that term may come to one of these site that have tons of listings even for small towns - however, they are also listing 'skilled nursing and retirement homes' under the umbrella of the term 'assisted living' - both of which are vastly different than assisted living - but an algorithm, not being an expert in the industry, wouldn't know that. So, people spend a lot of time on these sites trying to sort through information that isn't totally relevant - adding to time on site, and the appearance of quality but really a disservice to the user.
So, yes, to have one company command most of the adwords space, and then populate half of the organic listings in one way or another is becoming a troubling trend. Independent, honest sites aren't doing this - most of them don't have the time, staff, money, or conscience to pull it off.
Seems to me that one of the biggest assets that google has to weed through some of this stuff is with some of their own data. Although Google Plus isn't flawless, they can surely tell who the real users are who spend lots of time on there - users giving +1's to sites and content that is good. Of course, it can be gamed, but I think google should be smart enough to know who is doing that. Getting consistent +1's from people in the industry you are in, people who contribute to the community should be a pretty valuable vote for a site. Youtube, same thing - harder to game than facebook or twitter -they know who is legit on Youtube. Most of these big brand sites have very little of either, especially with their 'multiple domains' - often times nothing in the way of authorship, +1's, or even a face on the site somewhere telling the user who is behind it. No attempts to build trust.
As of right now, I have little hope for any independent sites, and little faith in the drumroll of the past many years that "Content is King'
Hopefully the tide will turn back.