Seeing it from the perspective of a network filesystem (WebDAV by itself is a lot more, albeit afaik has never been used seriously as an authoring tool) it is a bit over-engineered, but the real problem (expecially when dealing with CardDAV and CalDAV) is the clients/servers inter-operation, as it looks like no-one is able to respect the RFCs (check the amount of hacks the radicale project or davvy needed to make OSX clients happy, or the differences between lightning, korganizer and so on). So the reason is that my patience ended :)

Speaking from the perspective of someone who touched WebDav and then wrote my own server alternative. WebDav is really that bad. It has a special combination of using XML to be theoretically extensible while generalised to use the lowest common denominator of features.

I can't recall the specific details, but I certainly remember the pain. Apart from the inevitable and unnecessary translation from XML to a JavaScript object. I seem to recall there were weird cases where the XML format produced a different structure for cases where directories contained a single file.

In the short term I found capturing the output of "ls -al urlpath" was vastly easier to deal with.

In the longer term I wrote a server https://github.com/Lerc/userserv It might be worth me revisiting userserv to switch to the SpockFS protocol. Currently I use a websocket backchannel to do anything more complicated than static serving.

WebDAV doesn't go far enough; this exposes enough methods to provide a POSIX-compatible filesystem.