only the modern that ever becomes old-fashioned?

This is a tricky question, because it depends on your definition of "modern" and "old-fashioned." Here's a breakdown to help you think about it:

Modern:

* In the sense of "current": Everything that's currently considered modern *will* eventually become old-fashioned. This is simply the nature of time and changing trends. Fashion, technology, and even societal norms all evolve.

* In the sense of "stylistically contemporary": This is where things get interesting. Some styles, especially those rooted in function and simplicity, can be considered "timeless" and remain relevant for decades or even centuries. Think of the Bauhaus movement in architecture, or minimalist furniture design.

* In the sense of "a radical departure from the past": This is often associated with periods of rapid technological or societal change. However, even these "revolutionary" ideas eventually become ingrained and normalized, leading to the emergence of new trends that are considered modern.

Old-fashioned:

* This implies something out of date, no longer in fashion, or perceived as outdated. What's considered old-fashioned can vary depending on individual taste, cultural context, and the specific field.

So, the answer depends on your perspective:

* If "modern" refers to anything currently existing, then the answer is YES. Everything will eventually become old-fashioned.

* If "modern" refers to a specific style or period, then the answer is NO. Some styles remain relevant for a long time, even as new trends emerge.

In a nutshell, the idea of "modern" is fluid and constantly evolving. What's considered modern today might be considered old-fashioned tomorrow. But some styles and ideas transcend time and remain relevant for generations.