My professional experience says otherwise. There's always more work maintaining/enhancing sites than creating new ones.

By the way, Rails is the craze from maybe 10-6 years ago. consider e.g. [0] But it is still far, far from dead. Time flies, but not as fast as you suggest.

[0] https://www.google.ca/trends/explore?date=all&q=ruby%20on%20...