The difference is that for 5 years Black Belt items were one of the least wanted items from mobs that everyone did everyday. Lets face it, after 3 or 4 Wyrm Beards a linkshell was generally done with them but continued to camp fan/nid every day for the other gear. This allowed BB items to continue to flow into the system, many times to people who had no intention (at the time) of leveling monk.
Fast forward to a time where that other gear is worthless. Now the ONLY reason to camp them is for the BB items. That means 1) You won't be buying them anymore. Period. 2) Your linkshell won't be camping anymore. Period. In that regard BB items have gotten much more difficult to obtain despite the level cap increase. You can't get one as a 'side benefit' of camping kings because nobody does it.
BB items are in a rather unique position at the moment. It is, no doubt, the most highly desired item from the days of the 75 cap but the events to obtain them hold no rewards for anyone other than monk. Kings don't drop good gear anymore (other than 2 d. rings a year). KS99's use triggers that players don't renew anymore (kindred seals don't drop in abyssea and farming 99 of them would take 10ish hours minimum). It is in that regard very similar to the PUP attachments found in the ashu talif. Sure the event is easier because of the cap, but who (other than the person who needs the bb item/attachment) wants to do it? Nobody. Not when you can make more gil selling razed ruins or minikin. Not when instead of 20 KS fights you could have done 50 Amuns.