Not in my experience. That's why the distinction is made between "virtue signalling" and "actually being virtuous".

It's more akin to showing up to a date wearing fancy clothes and driving an expensive, but borrowed car. Giving the symbols of wealth while possessing none, to fool an audience.

Many of those I've seen signalling their virtue the loudest possess the least.

The reason for the growth and awareness of the phenomena? In prior times, one must perform virtuous actions to appear virtuous. Now, it costs nothing, takes no effort, and carries no risk; it's as simple as typing 140 characters into a phone screen.