Nobody has mentioned on which server they play on. I play on NA and EU with chars over 2200AP on both.
What I've noticed is that on NA nobody just LFP on F8. People seem to wait in the lobby for somebody to post a dungeon in F8 and then there's (sometimes) a quick surge of people to join the dungeon.
On EU on the other hand, people do indeed still just LFP up to CC and it fills relatively quickly if the dungeon is on the daily challenge. For that reasons, I prefer to progress my chars on the EU server now.
The truth is, the population of BnS is dwindling. If BnS Buddy is to go by, I only ever see a population of between 600 - 800 now. And that's at different times over a 16 hour period.
For those that says newbies should create their own parties to run dungeons, they're probably unlikely to since they don't know it well enough to lead it. Remember back in the day when you could just LFP in F8 if you had the minimum weapon requirement for the dungeon and/or reached the story requirement to run them? If we could bring this back and players could just LFP the dungeon, it would certainly help the newer players.
For those that say new players don't ask how to run a dungeon to learn the mechs, I've seen people ask at the first boss and instantly other players just leave the party. It's no wonder then that people stay silent and hope for the best.