No it doesn't.
There are plenty of freely available materials online and material wizard that is embedded inside MXM is pretty powerful to create base of lot's of materials.
Honestly - Material wizard in Maxwell is unlike similar initiatives in other render engines - it is on of those underrated features that NextLimit is shy promoting (not sure why though - huge time-saver).
It can create base structure of very wide range of materials.
Bundle it with free textures from
or dozens of other similar resources .. not even mentioning hidden gem - https://share.substance3d.com
- with free SBSARs and so much more (supported by community)
and you got pretty any material you need.
Honestly Material library is definitely a great idea - but I, personally, think that it should be curated and open for users to share their material creations - so that we can organically grow it (instead of having thousands of coloured plastic from RAL collections