People are really bad at knowing what they want. This isn't an opinion. It's scientifically proven fact. This is so prevalent that the
Wikipedia article has almost 200 entries. ITT people complain that they don't want true RNG, they want one that increases success % as they fail. This is a perfect example of people not knowing what they want. Studies have shown that your happiness is much greater when the success of the outcome is unknown and unexpected than when the outcome is expected.
Scenario 1 (true RNG, 5% drop rate): Atma drops from 1st FATE. Very unexpected, Player gains 100 "units of happiness".
Scenario 2 (true RNG, 5% drop rate): Atma drops from 22nd FATE. Within normal boundaries of expected value, Player gains 50 units.
Scenario 3 (true RNG, 5% drop rate): Atma drops from 50th FATE. FINALLY! Player gains 150 units.
Scenario 4 (weighted RNG, drop rate increases over time): Atma doesn't drop from 1st FATE. Player grumbles about having to grind out 49 more FATEs in the zone to max out the drop %. Player gains 20 units when it finally drops.
Obviously "units of happiness" is a made up measure but this roughly illustrates how removing the peaks and valleys of RNG would turn the game into a bland experience. There's no adversity and thus no elation at having conquered adversity if 1) success is guaranteed and 2) the emotional curve is flat. Modern AAA video games are so focus tested and all the sharp edges are sanded down to hell, creating very smooth, very polished, very boring linear experiences. RNG contributes to keeping the emotional highs and lows over the course of gameplay by introducing the unexpected.