Well, there are still ongoing bonus XP promotions for people purchasing "cartes abonnes". It's not double but 50% more, and there is also the fairly generous gain of UXPs through sustainable aviation contributions which BA do not have. I should add that the vast majority of GGLs (myself included) have always qualified without needing the double TP BAH promotion due to its restrictive conditions and the fact that many of us don't like BAH anyway!

In fact, when BA launched their double TP promotion, there was a debate not similar to the one taking place here as to whether BA was just diluting GGL and likely to flood the CCR with a bunch of people who are not really frequent flyers. This didn't happen, and whilst no airline releases figures about their exact number of elite members, in several discussions, BA have been very explicit that the number of GGLs has decreased quite significantly in the past couple of years, and indeed, complaints about the "CCR being crowded" at peak departure time when the world first recovered from Covid have completely disappeared on FT despite BA F cabins being fuller than ever.

Also worth noting that according to Raffles on the BA forum, there is a cap to the number of GGLs who will be accepted as FB Ultimates.

PS: Each airline has its own individual rules on earning. As noted above, the main advantage of GGL historically was that you would earn on any OW flights, but it is worth remembering that since the promotion is targeted at UK residents, typically, the vast majority of their flying is BA anyway. Conversely, it is worth remembering that with BAEC, you earn negligible TPs when you fly economy (unless full fare) which is in sharp contrast with FB so in effect, the people being matched will essentially be people who only fly J or F long haul as it's effectively impossible to qualify to GGL otherwise (unlike FB where Y flights can make a genuine contribution towards your total target). Finally, GGL has no equivalent of FB's rollover miles. Many of us have accrued 7k-10ks TPs in a given year but even then you start again at 0.

In fact, when I looked at my own case, i would have clearly been easier to qualify for Ulti than for GGL (or HON). I appreciate that situations vary but I really think that on balance, Ulti and the "old" GGL are representing comparable conditions of qualification on average, albeit one might be slightly easier than the other depending on one's individual patterns. In my case, I stuck to GGL for years because it made more sense for my organic flying patterns, because I value access to F lounges on OW, and because of inertia (ie I had no major reason to reconsider). I'm now seriously asking myself and I can assure everyone that if I take the jump I will take it fully and certainly won't be a "cheap" Ulti and even less so just in to get the benefits (I'm plat for life anyway and typically book J long haul in the first place so I already have many of the advantages and the upgrades will be less valuable for me than for many others since I typically wouldn't have much use for them long haul).