A million dollars at 4% is $40,000/year. After taxes, maybe $2500-$3000/month. If a person has a paid off house and car, and has everything else they will need to live a happy life, to me this much in today's dollars is a huge amount of income (at least in the "flyover country" parts of the South and the Midwest). No need for frugality here. No need for a "cheap but good lifestyle", IMO.
The big unknown is health insurance but that is exactly what it is - - a big unknown. For all we know, it could be free by the time these kids retire.
I think this article is feeding some Poor Little Old Me (PLOM) tendencies in younger generations. Not to say that they have a copyright on those tendencies, but still it is what it is. I think they have serious challenges ahead, just as we did, but I just can't feel sorry for someone retiring with a million dollar portfolio if he has otherwise prepared for retirement.