In response to the readings, I think responsive design is essential because it’s a digital way of engaging with readers. If the website is stagnant & does not do anything to hold the reader’s attention, they may be more easily inclined to leave the web page.
As far as app vs. responsive site, I would generally say responsive site is the way to go because people value the space on their phone & if your site/outlet is not something they frequent, they’re not going to download the app unless it offers something really unique that websites cannot. 
A website I find to work well across all platforms is Amazon. I do not shop enough (or I dont want to encourage myself to shop) to have the app, but whether Im looking for something on my laptop or on my phone, the website is quick & easy to use. It conforms to the shape/size of the screen & despite all the different options/categories Amazon has, it does not overwhelm the reader. They are really good about minimizing tabs & making the interface clean & usable even on smaller devices.
I also think that having a responsive site is the way to go! Users aren’t going to download an app unless they’re frequent visitors of the site.
I completely agree with your thoughts about responsive design vs. apps. Most people would rather use a responsive site to get information quickly instead of taking the time to download an app.