you misunderstand their playstyles.
echo gets picks at moira grasp range and can defend herself rather well with a gm player, pharah forces the enemy to deal with her due to her oppression of either the backline or frontline while having 2 tanks as a meat shield.
the problem with dmg boost pharah is not her primary it is her barrage, every single time she was meta all abilities were dumped into her barrage.
why have a base kit genji when you can have a dps earth shatter?