You're mixing up design "fads" with solid principles.
> large icons, large fonts, wide margins
I have 20/20 vision but even for me, all these are boons. It's the "design types" that want small fonts because they look cool. But for reading, give me a 14 or 16 font any day of the week, much more relaxing on the eyes.
All those things you're complaining about improve readability and discoverability.
I can't even imagine how people with bad eyesight think about this topic...
> and slow response times because everything has to go through JS/XHR
This does, indeed, look like a (software) design fad.
I feel like I'm not understanding what your saying. Zooming is easy. I have bad eyes and zoom in on websites all the time. Simple sites like LWN work great, but every "magically interactive overly-designed" site breaks immediately. Large icons start overlapping/fighting with each other and the text. Wide-margins end up squishing the site to one or two word columns
If you like gigantic fonts, feel free to press "Ctrl +" in your browser. I'm sure there's also a setting you can change to make the fonts larger by default if you're having problems with your eyesight.
For me, "design elements" tend to make content harder to consume.
> it just feels clunky
Pages that load megabytes of JavaScript to display kilobytes of text feel clunky. The modern trend toward large icons, large fonts, wide margins, and slow response times because everything has to go through JS/XHR makes websites that keep with today's design fads feel like toys, while websites that present information without a ton of JS and CSS baggage feel like tools.
I feel like design fads are partly a clever marketing ploy to keep web designers in business -- "it doesn't look modern" shouldn't be a justification to plop down the big bucks to redesign a perfectly functioning website every 3-5 years, but it is.