Am I right to understand that you and the legions of "sensible people capable of making good decisions" in the Linux ecosystem (hereafter collectively referred to as "Red Hat" ) are going to fork the Linux kernel ?
I am in no position to do that, as I am not a Linux kernel decision maker. But I know a little bit about storage and file systems, and if you think about it for a while, you will find that ZFS has great advantages, which Linus happens to ignore in his rant. I hope that the better mousetrap will eventually succeed in the marketplace, and ZFS will be fully supported on some Linux distribution and in the kernel. I've explained why I think ZFS is good several times on this forum; in a nutshell: built in RAID (which much shorter MTTR, which translates directly into higher durability), complete on-disk checksum coverage, support for multiple RAID levels and relatively dynamic transition between them, and a mostly workable user interfaces (sometimes a little wonky, sometimes missing a few features, but better than everything else that's free).
It makes sense since Systemd (hereafter referred to the "1.5M line chaos") has failed big time.
A: Systemd has nothing to do with ZFS. You can use both, one of them, or neither. If you use both, you can integrate them somewhat, but you don't have to.
B: The claim that systemd has failed is ludicrous. It is the default init system on the largest Linux distribution (measured by installed paying customers, not kids with their laptops in dorm rooms). Matter-of-fact, I use it all the time, I have written services for it, and it is perfectly workable. My fear is that systemd is succeeding too well, and will take over the market for init systems so completely (simply because it is better) that we will lose intellectual diversity.
C: Does this mean that I like systemd, or like its creator Lennart, or think that he is an upstanding person or good software designer and engineer? Hell no. I don't like working with systemd, I think Lennart is a sociopath, and his idea of software design is to pile his old solutions on each other and ignore other people and real-world requirements. But for better or worse, the result works well enough, and is taking over. Having an apoplexy over it won't make it go away, and lying and spreading fake news really won't help.
Honestly, your fears might still come to fruition. It's possible that people actually listen to Linus and ZFS gets unsupported from the Linux kernel, and therefore the Linux ecosystem. To me, that would be irrelevant, because I run ZFS on FreeBSD. It is also possible that ZFS on FreeBSD will wither away for lack of volunteers to maintain it, in particular if too much of the volunteer energy gets spent on battles between Linux and other operating systems. If ZFS becomes unusable for lack of maintenance or platform, I would have to migrate my home server to another file system. While painful (it would take several weekends), that's perfectly possible. And given that I have friends in the storage industry, I would probably end up with a technically good solution, even if it requires buying licenses. There are other good file systems, but they are not free, but you can find them.