In 2019, limits on IRA contributions (and Roths) are increasing from $5500 up to $6000 and you can add another $1000 if you're 50 or older. The 401k limit is going up $500 to $19000 and you can add another $6000 for 50 and up.
I can appreciate that not everyone can start saving early on but a very realistic scenario that I have laid out before is that it is very plausible for a couple in their 50's to have their house paid off which frees up money, the previous mortgage payment, every month to put into savings. Additionally, these people can forgo replacing their 5-6 year old vehicles which frees up even more to potentially go into savings. In starting to frame this, it isn't a huge leap to see where they might be able to start socking away $2000/mo and max out at least one of the partner's 401k, all the better if both partners can max them out.
Starting at 55 with no savings but now being able to max out a 401k contribution could easily get someone to $400,000 by age 70 (the contributions alone would add up to $375,000 plus any market gains plus even a nominal employer match). Retiring at 70 may not be ideal but the harsh reality is if you're 55 and have no savings, then you have to expect that something might have to give--in this case working longer.
Additionally, working until 70 allows Social Security to continue to grow. Waiting to 70 could realistically result in SS benefits in the neighborhood of $1800 (based on 2018 averages) for each partner plus another $1300/mo from the now $400,000 retirement plan (assumes the 4% rule for withdrawals) which all adds up $5100/mo. If only one spouse worked then it would drop by $900 to $4200/mo (spousal benefit is half). That all sounds pretty good for having zero at 55. Those dollar amounts may or may not sound like a lot to you but it is enough to stay comfortable even if a lot of sacrifices have to be made.
You may think there are obstacles that prevent you from doing this and while only you know what your particulars are, it is very encouraging to have a path to solving your own problem and great satisfaction in succeeding at solving your own problem. As Joe Moglia said, no one will care more about your retirement than you.