Gonna address a few points in order:

1) You're not confident building a party for an NM you don't know the strategy for? Do some research in BG's threads, they have whole sections on all three Escha areas within the first pages. Or even better, do what those forerunners did and throw yourself at it to see what happens. At worst, you're out some accolades or some fish mithkabobs, both of which are very easy to get. The "high-tier players" didn't just magically know how to fight these mobs. There were plenty of wipes in early experiences. If people get angry and quit after one or two losses, then they don't have the patience to progress in this game anyway. We build and learn from losses.

2) The "insane" Accuracy needed is in most cases not that insane until you jump to the higher-tier fights. Middle-tier stuff, I can hit accurately on my un-Gifted RUN at about 1050ish accuracy, and Sushi makes it trivial. Most of what you're going to need is going to be in the form of accessories; Ej Necklace off of the AH is +15, Steelflash/Bladeborn Earrings or Dudgeon/Heartseeker Earrings are +8 Acc/Atk and a bonus, easily soloed by doing individual NMs as opposed to Delve. Anguinus Belt from Abyssea era is easy, that's another +15, and then you can do a number of capes, like Kayapa for +10, or many of the job-specific ones. Using BST, for example, turn accolades into Refractives and work on getting an Acc+ augment to pair with the +10 already on it. Visible slots are generally going to be Taeon at first, but it's still something you can target simply by using Snowslit stones. If you need gil, farm Alexandrite (5~6k each on Valefor) or Dynamis, and build sparks to convert to gil. Etc etc. It's all tiers, like stated.

3) Back in the day, that difference between a mediocre and a well-geared 75 was just as bad as it is now. I remember comparing my BLU to others, doing a SATA Cannonball and falling several hundred points short (which back then was a lot!), comparing gearsets and seeing that I'm missing HQ gear or other similar. Where my DRG was there to maybe hit things but if you weren't a SAM and couldn't deal the damage that they got with their SA WS then you were mostly just fodder. The difference is about the same, it's just more pronounced now, imo.