What is different from a FC helping and a bought clear? Usually skilled FC don't even care if their new mate dies (unless it's really still tough content), oh you died to Titan.. whatever - go get some popcorn~ I have no idea if it was hard when released but when I finally got around to Ifrit in 1.0 no one was doing it, so I had three generous level 50s come in and rofl stomp him before my cutscene even finished (I shouted for 2+ hours lfp, three people came in because they felt bad for me lol). I didn't "deserve" it? Or if I had paid gil I didn't? Or it's not important because you don't care about that content now/ it's not your content?
I understand getting people who didn't learn their job is annoying to play with when you do content where you NEED to know at least majority skill play, and I wouldn't mind if certain contents were gated behind well designed skill test Maat like fights (you do your rotation and play near peak performance, or don't pass - I probably would benefit from these as well). Just don't make it like 250 tutorials, lol.
But it seems like the major complaint here is "I don't want to play with them, I don't like them, get them out of MY content". Which I would just laugh and say it's never going to happen, if people buy their way into 4* crafts, buy their over 9,000 gear, or whatever they still HAD to do work to do that (unless they bought the gil). They've done WORK and DESERVE the reward.
If you're complaining that people want to offer no work (money is a form of trade-able work) and get things, then I'd just say no one likes them too lol. But usually people wonderfully skip the part where work is offered and just don't like they're aiming for something you (whoever) doesn't want to share, it's mine, my own, my precious.
Buying gil is punishable, so we already have a solution where one need lie. Ensuring terrible players are less often in DF/PF is harder and to a certain extent impossible, also it's important to realize that people may know their job but don't know the content - dying cause you're new is different than dying cause you decided to stand in all the circles and ignore class basics (also some mechanics are just rough no matter, like lag sensitive mechanics, just complex ones in end game fights - that's why they're hard).