With Mondriaan, you made a very ...
wrong assessment.
One cannot assess what he did to initiate modern culture, design and architecture in the "new world" and as part of other classics in what was assessed modern culture.
OK, we deviate, but believe me that I can name you 100 cultural trends which's roots can be derived from Mondriaan's and contemporary artists.
We may not underestimate what we see as simplicity these days, as it still is genious by-the-way, and was an undescribable break-through at those times.
It is amazing how artistical quality continues - in cyclic periods - to be appreciated and depreciated and vice-versa.
Weird phenomen that we simply cannot fix ideas, such as: we believe this is an absolute beauty, now and forever.
This also applies to watches (...trying to bring the subject back...) and - apart of watch size - this is also a trend, surely commercially defined, but still our own eyes and mind are also subject to trends.
Thanks for reading,
Ciao, Rob.