True, but GluJS is the exception, which is why I point it out.
It appears to be designed to work on top of UI’s which are configured in JSON - currently it is a layer on top of ExtJS, and appears to be the inspiration (to put it kindly) for the new MVVM model in Extjs 5.0.
I have been in contact with the developer of GluJS, and he seems open to providing a version of GluJs independent of ExtJS.
I have been building reactive applications for 12 years, and have contributed to a few (the ones that are based on html templating), so feel confident saying that GluJs would be a relatively easy way for Webix to acquire MVVM functionality.
David