Can someone explain « comment en sommes-nous arrivés là »?

Question

I've always been taught it's « arriver à quelque chose » so I'm a little confused why in this video at 23 seconds the presenter says the line « comment en sommes-nous arrivés là » not « comment y sommes-nous arrivés là » or just simply « comment sommes-nous arrivés là » without en or y because I would've thought the là was enough to indicate some sort of position. Could someone explain why it's « en » and what the difference between the three options are (or if my suggested ones are just invalid)?

Answer 1

"En" wears many hats but here it seems to be an adverbial pronoun that denotes initial situation or place:

Comment en (= from where we were) sommes-nous arrivés là (= to this current state)?

The sentence: « Comment y sommes-nous arrivés là ? » is incorrect because “y” and “là” are redundant.

« Comment sommes-nous arrivés là ? » is correct but you lose the expression of contrast of the first sentence.

Answer 2

There is a noticeable difference between

Comment en sommes-nous arrivés là ?

and

Comment sommes-nous arrivés là ?

In the former sentence, là refers to a situation that affect us (a state of affairs, a condition) while in the latter, là might just mean a physical location.