It won't happen though I dare say - the whole point of the 7th Umbral Era events being written into 1.0's storyline in the first place was to give a narrative reason for the complete change in map design from 1.0 to ARR - 1.0's storyline and all the connected events was therefore a once-only thing never to be repeated (in fact, the achievement for completing the 7th Umbral Era story in 1.0 was literally called 'Once in a Lifetime!').

So yeah, apart from the occasional Echo-vision of events pre-Calamity, I can probably safely say players will never experience that again. Yes it's unfair for those who didn't play 1.0, but that's life sadly.