Why do most Desktop sites look just like Tablet sites now?

Since all of the Adaptive- and Responsive-Design trends have taken over UX and web design, I've noticed that the vast majority of sites I go to - and which I browse predominantly on a laptop or desktop with a big monitor - look almost exactly like they do on a tablet.

I had thought the idea of these new trends was to scale sites to the browsing experience being used. All the articles I've read on the subject talk about scaling sites to phones, tablets and desktop, and using appropriate design for each one.

However, so many of the sites I'm going to on my desktop have HUGE images, HUGE panels, FLAT design, HUGE fonts, big ol' KANDY-KOLORED GUI elements, very very VERY simplified interfaces, etc. Everything is waaaaay dumbed down from the desktop GUIs of the past (which, in my opinion, were a lot more useful and let me do a lot more with far fewer gestures; I could see a lot more on the screen at once, which was helpful).

That is... they look just like their mobile counterparts.

Yet when I've looked around the web using some creative Googling, I've found just about nothing discussing this. Most of it are designers talking about how great these design trends are, and how to scale to mobile devices; almost nothing about how most sites aren't actually scaling to Desktops (except in fitting the screen, pretty much, and in no other way).

Isn't there any discussion of this?

Why aren't companies and designers making more use of the desktop experience? It's like they designed to the tablet... and just stopped.

• Tim