Wow - I'm certainly not happy to understand the details here. I thought it was more like the others where you needed activity every 18 months. This is a very different story.
I just booked my family of four on Virgin LAX-JFK. The price was almost identical to Delta, which I now realize I should have chosen. I probably would have made medallion on Delta, plus the miles would all be in one place. But, I figured, they have an FF program, so I'll try it. Had I realized, no way.
What's crazy is that their price is competitive with Delta, but once you factor in the miles situation, it's not even close. I figure for every five coast to coast flights on Delta, I get one free. I probably make enough to get that in under 18 months, but my kids don't. So I just blew 20% of the ticket price on their fares - and that adds up to a decent amount of money.
Unless/until this policy changes, these will be my last Virgin flights.