I think your comparison with Microsoft is apt here. I know an increasing number of users and sysadmins looking for MS alternatives precisely because of that sort of experience. One friend recently said he was looking at moving to Apple next time because Windows 10 is such a pain and I have lost count of the number who are looking to move to Linux now. Even my 85 year old mother is asking me to move her onto some alternative because Win10 is causing her so much grief, and she never wants to change ANYTHING. She has also said all her friends with computers are complaining endlessly about Win10.
After that sort of experience, no IT professional is going to go with something as buggy as this.
I have just installed Nethserver as a trial and it has been smooth as silk in exactly the same test environment (except when I forgot to set the network to Virtual Host instead of internal, but that is hardly their fault. Shut down, reset the NIC and reboot. Up perfectly!) The contrast with Zentyal could not be greater than that with either version 5.0 or 4.2. I tried 4.2 in the hope that it would be more stable as I assumed that the paid for version would be similar to that. Either the two bear no resemblence at all, in which case there must be two entirely different development teams which I think is extremely unlikely and even less desirable, or that the paid version is in any practical sense no better.
I really wanted Zentyal to work. I still do. I liked the way it appears, both on paper and on the screen, but the decisions the management are taking are just wrong IMO and will drive the project into the ground. One can only hope that a group of developers will leave and fork it in the same way as happened with the birth of Libre Office and more recently Nextcloud.