I wonder if there's some way to simulate the row by row image loading. I guess that's not the point of this website, but that would make me feel nostalgic.
Just throttle your router settings for download/upload - have fun!
In all seriousness though, people designing websites should be given the shittiest connections possible and old computers (between 5 and 10 years old). Maybe then we'll end up with websites that haven't got more JS than content, broken CSS and images that push the page download over several megabytes.
Chrome Dev Tools let you simulate shit internet connection (2G, slow 3G, fast 3G, etc.) and Google encourages to this for development for the reasons you've mentioned.
It's awesome it exists, but useless if nobody uses it. I think the Google homepage is the only Google product I'm aware of that loads fast, minimal CSS and still loads without JS. Even on a modern computer, some websites have become completely unacceptable to run in the background (i.e. Facebook).
Installing NoScript and blocking external CSS was the best decision I ever made. Now use <25% of the RAM and <10% of the CPU I used to for the same number of tabs (in Firefox) - with a better experience because the browser isn't constantly trying to die.
You can see images load line by line today, if you throttle your network (either through Chrome devtools, or some external tool). Or just get a dialup modem, you probably have a provider you can reach, and the good ones can be plugged in through ethernet.
