The game difficulty is balanced so that for the most difficult battles, almost every player in the party must perform well, or nobody will succeed; we are very co-dependent on each other to make any progress. For people who are not in a 'static' group of elite players, this means needing luck in finding random players via Duty Finder or Party Finder groups. However, random groups of players have a near 100% failure rate. I've tried some dozens of different Titan (extreme) groups, but most fail the battle near the beginning even after many attempts, due to the actions of perhaps a few players in the team.
It's hard to get any team together in the first place to attempt battles, as PF teams can take an unreasonable amount of time to fill and asking assistance from the many players standing around Revenant's Toll usually garners no reply. I think part of the problem is that once the most skilled players have cleared content, for whatever reason they don't feel the incentive to re-visit it or help people who are lagging behind, and the pool of available skilled players shrinks considerably.
Today I did come across a group of players who claimed to be able to beat any primal or raid, but they were charging 4 million gil per battle for their services. Primal battles only last about 10 minutes if you succeed so it's not very draining on anyone's time, and 4 million gil would probably take me 18 months to save up incidentally by doing my regular routine of playing dungeons and such. I don't know why they think they should take 4 million gil from another player in order to get up and offer 10 minutes of assistance.
I often help people who are lower down the ladder without asking for anything in return. To see people who are incredibly happy and grateful to have finally beaten something which they may have been struggling with for a long time, it's a good feeling and an experience that leaves a good memory. Sometimes it just happens incidentally as I am seeking something for myself and somebody else benefits from my presence. It would be nice if the extreme mode primals for example offered something to incentivise the elite players to revisit them, so that other players may benefit from their presence. i90 accessories from Garuda, Titan and Ifrit have not been enough to encourage players to repeat them many times.
It would also be good if a reward was offered for joining a PF group and staying till the completion of the requested duty. I recently requested help for Hydra, but nobody wanted to help, I suppose there was no incentive for them, and my PF recruitment eventually reached an arbitrary time limit and was removed from the listings. The way things are now, I think it's very hard to find a group of 8 skilled players who are all online at the same time and willing to assist with a duty, and not charge an incredible amount of gil for their services.
Update: I've just had a look at the translations for the recent event which I believe has answers for my concerns. EX Primals will receive an expert trials roulette. If the reward is sufficient for this roulette, I believe it could bring back players who are good at these duties to help others who have not yet cleared them.
As for coil raids, I believe these are already scheduled to receive increasing amounts of echo, so it will be possible to proceed through them with anyone who is available to participate regardless of their skill level, eventually. I must say I am pleased with the way the game is evening out. It makes me wonder if a roulette for raids such as binding coil and second coil turns will eventually be introduced as they become casualised to suit players who are randomly matched together through the duty finder.