Not sure if my observation is necessarily correct, but when I started to get into watches more than a decade ago, back when Swatch Group were still making the ETA ebauches, people were willing to pay more for a watch partly because of the movement, besides the aesthetics, especially when it was an in-house movement.
Hence, you would have a certain price range for the ETA movement-based watches (with the different grades of ETA having different pricing), and then modified movements, and then the ultimate being an in-house movement. From this perspective, it was not just about the viewable aesthetics but also what was inside the watch. For example, someone earlier in this thread mentioned about a Zenith, and that watch with the El Primero movement, is a watch most enthusiasts would pay the premium for, if they are interested in movements and because of the history behind that movement.
With ETA ebauches being withdrawn from the market, the other non-ETA movements came to greater prominence, the Sellitas, Seikos, Miyotas etc. I mean, they were always there, but the thing back then was to get an ETA movement (which itself had a few grades) as the entry point for a Swiss movement. During that time, most of the watch houses started to name the movements with their own caliber names rather than referencing it to the base ETA-grade movements. Over time, unless that watch houses mention it and/or if one is really aware of the movements, one does not know if a movement is in-house or otherwise.
Back to the topic at hand, with the rise of the microbrands, from an aesthetic viewpoint, as what was mentioned earlier, there is not much more in terms of the quality of materials as in how much more "ceramic" can ceramic get after a certain point. There can still be degrees of quality improvement, but the question is whether diminishing returns justify the premium payable for a luxury watch. Unless a movement is brought into the question, it is more of the service and brand name that comes after a certain level, and if there is a unique material type.
I have have both luxury and microbrands in my collection, and love them both (too many of them). With the luxury ones, it has been more for the specific movements and standout designs that I had picked them for, besides the watch material. A decade ago, for example, titanium and ceramic-accessorised watches were not so common as they are now.
If I were to start collecting today, I would not necessarily look at the luxury range with so much quality available in the circa-$2k and below mark. It would have to be a very special watch to get me to spend more above $2k, or $10k for that matter.
At the end of the day, buy what you like if you can afford it. As another poster has mentioned, not worth getting into debt for a luxury piece, after, a watch is just a watch, but it is what we make of the watch that makes it appealing. Just like a TV show is just a TV show but what we dream of that makes that TV show particularly appealing. Boldy go where no others have gone before; luxury or not, don't follow the crowd.