Release Date for 2018 Report Server Update

I really don't understand why there is such a lag in the release of new features.  If they are developed for the cloud and individual user, why does it take so long to release for PBIRS?  My company at this time can't move to the cloud due to our parent company policy.  I also have contractors that work on different versions and trying to upload their dashboards to my report server is not working for us.  I am wasting money paying a contractor for work and then having to redo all of them because they versions aren't compatible.  Also explaining to my IT Director that PBIRS doesn't have the features we need or aren't the same as Power Bi Desktop is not an easy sale.  We are paying for a product. We should have the lastest updates more than 2-3 times a year.   I understand wanting to push the cloud based product but for those customers that can't migrate in that direction - you need to have a roadmap for us and more releases.