thanks for raising this point, I’ll share some thoughts from my POV here.
First: Yes, there will be support for the PHP based ownCloud as we move forward with ownCloud Infinite Scale (oCIS). I can not make a concrete statement now how long that will be but it will be long enough to not leave anybodies usecase behind. The plan is that there will be reasons enough to switch to oCIS, so that users will be happy to migrate at some point.
Now to your point about loosing the ability to deploy ownCloud on a ‘ordinary web hoster’ with oCIS. It is right that this has been very important in the beginning of ownCloud and helped to make ownCloud widely adopted.
But with offloading the (mainly PHP-) dependencies to the underlying platform the PHP based ownCloud also put a burden to the admins: It has always been their responsibility to set up and maintain a working and secure “base platform”. Both points are not trivial, especially with extra functionality delivered by special PHP modules. Also on the long run, when security updates have to be delivered for the entire stack. While it might have been ok ten years ago in the small “familiy use case” to trust that every PHP stack is maintained properly, I do not think it is still today, not even in the smallest use cases.
With oCIS we’re pulling most of the dependency hell into the development: Golang bundles the depending parts into the (single) binary and they are maintained by the provider of the build which is ownCloud. What can be downloaded with the coming GA version is a carefully crafted, dependency resolved, maintained and also CI’ed and QA’ed solution. All that needs to be provided to run it is a very basic containerized, virtualized or bare metal environment with very few extra deps. That is way easier than providing a full LAMP stack. I hope you agree on that.
Microservices architecture is btw nothing ownCloud is doing on its own, but an industry trend used in many so called ‘cloud ready’ apps. There are already very attractive hosted offerings for environments, and that market will evolve.
I hope this enlightens the main points of this aspect of our architectural move a bit.