Comedy aside, CSS isn't the problem, but if an experienced web-dev can't make a site without learning for 5+ years and then feel like they have no knowledge of web development then we have a problem, and that's where we are now.
The problem with the long list of frameworks and libraries available is that there is no easy way to make a web2.0 site without years and years of learning and then the resulting site is a mish-mash of what works without it being easy to maintain. Sitting here looking at .NET & angularjs 1.x and wondering where it all went wrong (actually, not the.,NET part, that seems to work).
99% of websites can be done with either a static generator (lean) or WordPress (somewhat bloated, but really mostly standard libraries that can be cached and/or served by a CDN). The remaining 1% are the really bloated ones and sure they are the ones that we visit all the time (medium, BBC, whatever). But it's certainly possible to make a site with not too much knowledge of web development.
I was talking about work as a professional developer. We can all 'make a site', there exists any number of solutions for that, CMSes like Wordpress, Drupal etc don't count in this argument unless _you_ wrote Wordpress or Drupal from the ground up. Being a wordpress hack isn't being a developer. You won't ever be asked to write something straightforward in enterprise, you'll need to know at least HTML5 & CSS & angular 1.0 & 2+ (or similar) & docker & gulp/grunt & backend & databases & jenkins & MVC & node/npm & version control & bootstrap (or similar) and and and.
99% of sites outside of a company that makes real money and doesn't just serve a page are sites that aren't what developers actually do at work.
That's flash.