So, yeah: What's changed in 20 years is the amount of external crud that people tie into their software, thinking that it saves them time and effort.
If you were making websites 20 years ago, then you must remember how much of a pain it was to take into account different browsers, right? How much of a pain it was to take into account different screen sizes and device resolutions? How accessibility for disabled people was either entirely ignored, or just a second thought after the site was done?
Using something like jQuery for DOM manipulation (created in 2006, extremely stable) and/or Foundation (created in 2012, widespread use along with the competitor Bootstrap) for responsive design and accessibility features, solves way more problems then it introduces.
And what happens when its time to re-brand? You want to manually edit tons of CSS to change the feel of a site? Using something like SASS/SCSS you can use variables in CSS and and manage many tiny css files devoted to specific features, and then combine then into one compressed css file when you deploy.
I haven't done a lot of front-end work in the last decade, but I work with the team that does, and the things they do easily, that would have taken me/my team weeks way back then, is pretty astonishing.
It leaves a lot of time for the more important things, like usability studies, user experience, audience evaluation, finding out if the site actually accomplished what you wanted it to.... rather than spending weeks or months hand coding css/js to display properly across all browsers and displays.