<i>Imagine if you want to change a link on a sidebar and have to re-build every HTML page served by your CMS to do that.</i><p>On the other hand, doing the processing on the client side means that work would be done <i>every single time</i> by <i>every single client</i>, and the result of that work isn&#x27;t even preserved.<p>As decades of programmers have had absolutely no problem compiling software with many, <i>many</i> more dependent files than pages on a typical HTML site, I suspect the problem is in the implementation and not the concept.<p><i>build or host their own server-​side analytics or commenting systems</i><p>I&#x27;ve not written any analytics before so I won&#x27;t comment on that, but it&#x27;s funny you mention commenting systems since a simple one (textboard-like) is literally less than a day&#x27;s work.