Yeah, Intel is being more cautious this time around by using an intermediate internal test node, although I think implementing GAAFETs first is the right move.
Doesn't everybody do that? Even when you plan on releasing two features together it makes sense to have separate teams solving their own problems independently. I don't know enough about the process steps to be sure, but I'm guessing that for test shuttles developing these features you might be able to skip some steps (especially during early development) if you have split them up and get results sooner than if you were trying to test both features at once on the same wafers.
TSMC seems to be taking a stepwise approach with GAAFETs themselves, first implementing them without any real density enhancement (or improvements in power routing) so they seem to think implementing GAAFETs without scaling (N2 reported as 1.1x) is worth splitting out. I would expect they will split up BPR and BSPD as well since one depends on the other. There is nothing requiring them to wait a year between releases if they have things ready earlier, or delivering features from both streams together (i.e. denser GAAFET libraries might come with an initial step in improved power routing) but we'll have to see about the timing.
While Intel may be doing internal nodes to reduce risk, by so publicly setting a goal of releasing everything in one big shot to try to retake process leadership they are setting themselves up for trouble. By marketing all these features together if they run into trouble the engineers are running the risk of encountering resistance from management to the truth and publicly admitting yet another failure to deliver. They'd be forced to either delay the whole node to wait for the missing features to catch up, or release without everything that has long been promised. The pressure on process engineering will be immense to make the whole enchilada arrive as promised, even if yields are terrible and management tells them "we'll just accept poor yields for now and fix it in production" rather than admit anything is wrong. I mean, look at how long they denied the truth about 10nm?
So even if the day approaches when Intel says they will begin shipping CPUs on this new node and claims everything on is on track I will STILL be skeptical it will really happen in true production quantities.