I’ve been involved in the web for a long time, and in that time a lot of things have changed. It went from using tables for layout to floated DIVs (and soon to flexbox) for layout, from
<font> tags to CSS styling, and from server-side everything to JS-only frameworks.
In all of this change, a process known as progressive enhancement was adopted by a large number of developers. This worked on the idea of ensuring that all users of your site, regardless of the technology they used (be it an old broken down version of IE, or the very latest copy of Chrome) should be able to use the site to one degree or another.