Echo is for old content, and it still doesn't win the fight for you. As far as I know, the latest extreme primals and coil raids never have echo, and the amount you get on the older ones is meagre and doesn't help much, you still need to execute everything correctly. Echo exists for a reason, to ease things for people lagging behind. If you want a challenge, do the latest content, try beating Turn 4 of the Second Coil of Bahamut, and soon Ramuh extreme mode.