I think this is a very thoughtful article. As web devs we are much more likely to be developing and testing on beefy machines and beefy Internet connections than the general population is. Let's remember that we're building this stuff for other people, not just for us. :)
I'll take one issue with one thing in the article (emphasis added):
> The cost of that data itself can be a barrier, making the web prohibitively expensive to use for many without the assistance of some sort of proxy technology to reduce the data size for them—an increasingly difficult task in a web that has moved to HTTPS everywhere.
But: HTTP/2! It's only available over HTTPS, gives really significant performance improvements and is supported on Chrome on those low-end Android devices the article mentions (and basically everything browser other than IE11 on Windows < 10 and Opera Mini).
The "proxy technology" sounds more like Opera: it's not simply compressing the existing stream, it does things like aggressively recompress your images at lower quality or even size. HTTP/2 will deliver your 2MB hero image using 2MB of data. A compressing proxy will deliver a slightly uglier 100kb version.
Oh, and save a lot of data by never downloading the ads.
I remember many years ago when i had a 3G internet connection (which sometimes even had to work via 2G networks) for my laptop, the service would automatically recompress images to lower bandwidth and speed up times. To enable the connection i had to use a custom tool (it was essentially a fancy terminal - AFAIK it communicated with the 3G dongle using AT commands) which also had an option to adjust the (ISP-side) compression (i could disable it, leave it at default or make everything look like garbage but load fast...ish :-P).
I'll take one issue with one thing in the article (emphasis added):
> The cost of that data itself can be a barrier, making the web prohibitively expensive to use for many without the assistance of some sort of proxy technology to reduce the data size for them—an increasingly difficult task in a web that has moved to HTTPS everywhere.
But: HTTP/2! It's only available over HTTPS, gives really significant performance improvements and is supported on Chrome on those low-end Android devices the article mentions (and basically everything browser other than IE11 on Windows < 10 and Opera Mini).