There appears to be a market for very premium F, particularly in the Middle East and Asia. Carriers that are hubbed in those regions seem best positioned to support that demand - EY, EK, CX, SQ. For carriers that rotate aircraft through these regions of the world it does not make economic sense to dedicate a portion of the cabin to a product that does not sell well worldwide. Few carriers have dedicated route-specific fleets and so carriers like AF, KL, AA, BA and so on rotate planes on their route network - something like YUL-CDG-DXB-CDG-PHL, for example. When the premium destinations are a spoke and not a hub it becomes to hard to argue for a premium product.

It makes complete economic sense for these carriers to forfeit potential higher yields on those flights to normalize for the broader demand across their network. I think we will see more and more of this rationalization. I would not be surprised to see BA, LX, UA and QF drop or drastically reduce F (even further than some have already committed to doing). Might even make sense for carriers like KE, JL, NH, CA, CZ and TG to consider it. That square footage can be put to better profit use as premium business class. Even CI learned this with their 77W, which has no F.

Only in cases where a carrier is hubbed in a market that has high ultra-premium demand and can support that with the right product will it survive. EK, EY, CX and SQ seemed best equipped at this point.

What I DO think is interesting is what JetBlue are doing with Mint in the US market. It's a narrowbody business cabin in alternating rows of 2x2, 1x1. The 1x1 are equipped as mini-suites with sliding pocket doors. For now they do not charge a premium over the regular Mint fare for these seats but they will at some point. It's a way to attract travellers who prefer a more private space but are never going to pony up huge amounts of $$ for an F fare. I think that could be a model worth exploring. You'd essentially see planes operating with Y, Y+ (Premium Economy), J and J+ (a few well-planned business seats).