The limit isn’t precisely 5000!
What happens in EVO is that for each resource saved, MODx writes some lines to the cachefile: siteCache.idx.php
Then on every page load, MODx goes and request the cachefile. If you don’t have a powerful server this
will start slowing down your website. But it doesn’t stop there. Most snippets (e.g. Ditto) will crash and
the Doc tree inside MODx manager won’t render that many resources.