Looks like some people had really bad luck with this.
I got all the stones with both of my characters and didn't find it too bad. Especially since you don't have to do it for every relic.
Sure, I spent a few evenings and a weekend on it (about a week per character, I'd say),
but I also needed the silver coins for all the other rewards and some gear.
And once I had most of the stones, I started skipping the fates and critical encounters that couldn't drop the required stones to avoid burning out.
Meaning, I watched Netflix while waiting for the fates /CE's I needed. ^^

That said, no randomness in a grind feels certainly better once bad luck strikes,
but I would also argue that most players still prefer the chance to get something sooner rather than having to do something 100 times with certainty.
But that, of course, depends on the odds and the numbers. For me, for example, it was definitely more painful to do all the fates in all regions.
And aside from the Endwalker relics, all relics had some RNG-based fate farming steps.

However, I still think they should introduce a pity system in the near future,
simply to help players who couldn't complete the content when it was full of players.
Like for example, the ability to trade five stones for one stone of your choice.