Do you really think GNOME owes its "success" to it being able to be used in unlikely places? How are you defining "success"?
If you define success by its ability to run in obscure places, then sure, any change which limits this is going to cause GNOME to be a "failure". But that's not the only definition of "success" and "failure". Personally, I think the ability to run GNOME on obscure operating systems isn't all that interesting. For similar reasons, it really isn't impressive to me that NetBSD can run on ancient Amiga hardware. And in, fact, NetBSD's obsession of supporting legacy hardware slowed down their ability to run on modern hardware, I'd consider it bad and a direct cause of their "failure" in terms of market share as compared to say, Linux.
There's a similar issue going on here with GNOME and obscure/irrelevant operating systems. If that slows them down, then they should (IMHO) figure ways of not slowing them down. And in fact, it's not a complete abandonment of those lesser/legacy systems. There would be cut down systemd releases that would support what ever limited functionality that might be provided by that operating system. If Solaris doesn't have cgroups to provide resource isolation, then there's not much GNOME or the systemd/Solaris adapter layer can do to ameliorate the situation.
If you define success by its ability to run in obscure places, then sure, any change which limits this is going to cause GNOME to be a "failure". But that's not the only definition of "success" and "failure". Personally, I think the ability to run GNOME on obscure operating systems isn't all that interesting. For similar reasons, it really isn't impressive to me that NetBSD can run on ancient Amiga hardware. And in, fact, NetBSD's obsession of supporting legacy hardware slowed down their ability to run on modern hardware, I'd consider it bad and a direct cause of their "failure" in terms of market share as compared to say, Linux.
There's a similar issue going on here with GNOME and obscure/irrelevant operating systems. If that slows them down, then they should (IMHO) figure ways of not slowing them down. And in fact, it's not a complete abandonment of those lesser/legacy systems. There would be cut down systemd releases that would support what ever limited functionality that might be provided by that operating system. If Solaris doesn't have cgroups to provide resource isolation, then there's not much GNOME or the systemd/Solaris adapter layer can do to ameliorate the situation.