How will this work realistically? How will you convince employers to keep workers employed till 70? Especially in fast changing fields like IT where a lot of old knowledge and experience gets considered obsolete by those screening resumes. Sure, people might survive longer, but that doesn't mean all workers will be equally mentally or physically fit to still perform well at some jobs at 70 as well as a 30 year old, especially if they're mentally or physically challenging jobs.
I'm not talking about government paper pushing jobs, but private industry jobs with international competition where you need to be agile and up to speed to survive as a business. This system worked for the boomer generation in slow moving highly regulated industries like steel, rail and automotive, where you'd spend all your life at one company who'd promote you and invest in your training till retirement, but this isn't as common anymore. International companies now want things done faster and cheaper and can't be competitive keeping 70-year-olds on the payroll idling around waiting for retirement.
For example, here in Austria, if you're laid off at the age of 50, the chances of getting another job at that age for many professions are already next to zero due to rampant ageism, so workers in some professions end up on long term unemployment till retirement, yet the government agencies are not talking about this major issue and just tell the 50 year olds on long term unemployment to "make a more colorful resume to stand out"(I shit you not). You're also not allowed to take your contributions out of that pot early or all at once to fuck off out of the system and be on your own if you want, proving it is Ponzi scheme in disguise.