I've not written a site from scratch in a few years (3 or 4) until recently, CSS has got a lot more complex (and yet also slightly easier as most of the core is the same across 98% of in-use browsers).

I hadn't done flexbox or css grid, didn't know what rem was, hadn't used calc(), or media queries that target based on viewport size.

Just spin-up a Wordpress instance sounds easy but most people will need/want a few plugins and things start getting complicated fast.

Before long you're handling passing special headers by modifying .htaccess and looking at Leaflet.js source code ... just to stick up a simple WordPress site.

And you still missed a million 'basics' like resizing media appropriately and adding aria-labels, and your site is not SEO friendly, and you didn't handle backups yet, ...