Blizzard did it because they were on Expansion number 8 and their level cap was 120. If you leveled in WoW from 1-120 it was a very lonely journey THAT WAS TORTURE to get dungeon queues and raids are NOPEEEEEE

I promise you FF14 does not suffer from the poor design decisions in level that WoW does. The level scaling system in FF14 should have been adopted by Blizzard years ago but they are too stubborn to even conceive of designing their end game around anything other then raids or end game dungeons that quickly gets invalidated with the next patch.

Level squish would break multiple aspects of FF14 from story to deep dungeons. Maybe once FF14 gets up to 8 expansions and new people stop joining you could justify it but right now there is zero percent chance.