Eesh. That's rough. I can understand people not planning for retirement but not realising they haven't is something else, altogether.
My husband and I have taken the approach of enjoying life now and having "post-retirement jobs". We can't put enough away to sustain the life we'd want without basically sacrificing all the goods things in our life now (and for the next 15-20 years). Instead, we're chomping away at the mortgage to get that gone but, otherwise, future planning is minimal (we should have had a good pot from rental properties but sold out because everything about it was crap).
I have a private pension that's worth pretty much nothing, my husband has a teacher's pension, which is worth far less than they used to be, but we should be able to cover the bills and a basic life. If we want luxuries, we'll top up with our "post-retirement jobs", both of which we'll be able to do ad-hoc, and then when we're too old for those jobs we'll just have a quiet life together looking back on the good old days.
For us, working towards retirement was just not really an option without basically sacrificing everything (including children... As in, not having them in the first place, rather than treating them as a sacrificial lamb) for the majority of our healthy years together.
We might live to regret it but, until very recently, we've always held back financially and then, a year or two down the line, looked back sympathetically on those young uns wanting to reassure them that it all gets better. There is an element of assuming that trajectory will continue (in which case we will be able to save for retirement and possibly bring that forward) but we're not banking (LOL) on it.