So basically for something to be traditional architecture it needs to be part of a long spanning, continuous evolution?
Let's just say that western architecture started with Greek architecture. Greek architecture was adapted and heavily changed by the romans. That evolved into the various post/late-roman architectures (romanesque, byzantine) which evolved into gothic.
That's continuous, but I think you're undervaluing how drastic the changes were. The types of spaces made, the way structure was articulated, the purpose, the scale, the massing, and everything was super different, even just from Greek to Roman. Even today you just have to glance at a building to tell if it's Roman or Greek, and if you had shown a Greek the future Roman buildings, they would probably think they were really weird.
But those are just the physical changes, and while those changes were big, they were driven by even bigger cultural changes. could you imagine living in western europe with all of your roman buildings and all of a sudden all of these middle eastern looking buildings start getting built, with all kinds of weird pointy vaults and black and white stripes. Isn't that radical? It's continuous because the cultures hit each other and impacted one another and then continued evolving. But if you went back then I doubt you could find anyone who thought that byzantine architecture was traditional.
I guess the point I'm trying to make with all that is that the development of architecture during that time was continuous, but some of the evolutions were more radical than the others.
But anyway, aside from that, what happens after gothic architecture? Well stuff happens but most of the knowledge of the past is forgotten. Continuity is broken. Neoclassical obviously isn't an evolution from gothic, it skips all of those evolutions and goes straight back to rome and greece. But it knows so little about the architecture that they didn't even know those buildings were originally colorfully painted, and when they found out, they didn't care and kept on making unpainted stone buildings anyway.
If it's really an issue of continuity, shouldn't neoclassical architecture be disregarded? Shouldn't they have picked up on gothic architecture, and continued evolving that? And if it's about continuity, shouldn't they have started painting their buildings when they found out that's what they were supposed to look like?
And if it's an issue of continuity at all, then how does modernism fit in? The ideas and themes of modernism began at least in the 1700s, became more intense and explicit in the late 1800s, and became mainstream in the early 1900s. All along they have been evolving and responding to each other. So if you want to continue an active tradition, isn't modernism the right choice, since it's alive and well over a hundred years old? Or do you pick up at the tradition that ended at gothic, which died in the middle ages?
And aside from that, you have to consider why architecture is the way it is, and what causes evolution to take place. Are changes in architecture responses to historical events? You might consider each time to have a unique and special set of circumstances (culture, technology, politics, economics, war, etc.), "a spirit of the times" but then you think the same thing as Mies van der Rohe and you're brought back to modernism.
If you believe in things like "roots" and "evolution" in architecture that implies that time and history are linear, and moves forward. If the history of architecture is like a tree, doesn't that mean that the present are the leaves? And doesn't that mean ancient greece is somewhere underground?
The issue of "traditional" architecture is complicated and it brings up a lot of questions. And maybe some people have been able to find satisfying answers, but I haven't. Every way you look at old architecture, it points to new architecture today. I think old architecture is something we need to appreciate, and understand, and learn from, but it's from its own time and place, is stuck there in any meaningful way, and we need to build in the present.
I think the only way that "traditional" architecture can be the right thing to build, is if you reject that architecture has any meaning, and believe that it's exclusively an issue of style.