Where is everyone?
1. Demographic changes means more retirees, and smaller workforce. Literally less people to go around.
2. With low unemployment, everyone’s doing something else. Something harder to automate, or otherwise more valuable. It’s not like people are sitting around unemployed (except retirees).
What are they doing? It’s hard to know without combing through data in this moment, but people are surely avoiding minimum wage and low skill customer service jobs if alternatives exist in their area. Anecdotally, I hear people don’t like working in anything customer facing due to rude customers. I know someone in TX working at Amazon warehouses at an hourly rate much higher than retail workers rate. They used to work at a gym in rural California.
Until we get rising low-skill immigration to cover more of the low-wage work, expect service work to be understaffed. Or rising birth rates, or a drop in white collar workers.
A small point, but I think what you meant to say here is that there's a greater ratio of retired to employed people than there used to be, which is somewhat different than what you stated.
That said, I think this idea that we necessarily need some incredible amount of low-skill immigration to cover some drastic understaffing is bullshit propaganda put out to achieve bad wages and treatment of workers through basic supply and demand (drastically increasing the supply of labor). Technical innovations such as self-checkout lines and great security cameras and other tools of the modern age mean that you need fewer workers to do the same work.
As I think others have pointed out, the unemployment rate figures can be massaged in a lot of ways to be misleading. Actual wages should be the stat that tells you whether or not the workforce is too small. If wages are dropping or stagnant versus inflation, then claims of low unemployment should be considered laughable because otherwise wages would be increasing.
You also cannot trust the Department Of Labor's official statistics by themselves since there's multiple ways that the U.S. government covers up actual unemployment numbers. For example stay at home parents aren't included in the unemployment statistic even if they worked previous to that situation. People who have been unemployed for more than a year are not included. People on disability but who are in an employable state are not included. Gig workers such as GrubHub drivers are not included. Certain methods of self-employment such as traveling musicians are are not included. They pulled this trick a decade ago and they're doing it again to try and prevent another panic. The one difference this time is that instead of people losing a single full-time job like they did in 2008, many are now working multiple part-times and thus inflating the employment statistic slightly since technically they're never unemployed.
Then there's the gap that happens for employees. If someone has a part-time job and gets scheduled from noon to nine for closing back to back for four days and then gets nothing for the next three days that means they're not getting paid the equivalent of a full-time job despite possibly working just as many if not more hours. When you have lulls like this you need a second part-time job to fill them in, leading to things like ten percent of the current counted national workforce having at least two jobs. But many part-time jobs in retail and services want to monopolize the person's time since scheduling is based on the employer's availability and not the employee's, meaning that sometimes the employee will have to purposely dedicate days of their week to waiting in case either job calls them in. If the person doesn't have a free day and are called in while working one of their two jobs, they may be fired from the other job. When enough places and people have an incongruent schedule like this places run short staffed and the person is still wasting a day or maybe more idle. Then there's the other half of that coin of scheduling abuse, the supposed part-time job that uses that flexible scheduling to transform into a full-time job. I know that Wal-Mart will schedule you for no more than thirty hours a week and will stack your shifts back to back, sometimes with as little as eight hours in-between, just so they have enough leftover hours in your schedule that they can call you back to cover someone without pushing you into full-time or paying overtime. This makes working for Wal-Mart hell because you're rushed and then all but told to be on standby, giving you very little time for things like other jobs, appointments, household chores, and even self care. The end result of being yanked between two part-times or being held hostage by a full-time masquerading as a part-time is that eventually the potential employee gets cynical and stops applying for that kind of work entirely.
Yep, let's just exclude all the people who tell the real story here.
Every gen-z in my family (and neighbors!) also have 18-21 year-olds who are doing weird shit like working for two days up to a max of two weeks, then abandoning the job. I don't know what this is about ("working" once per quarter to get the work credits for Social Security?) or how this is captured by the stats, but they are by no means employed.
Get used to it. The emerging model is a virtual vending machine - if what you want isn't there, tough. If the machine breaks, well, sorry about your dollar, maybe it'll work next week.
If you want to talk to a human, start by getting rich. That costs extra.
That should have freed up lots of people to handle the special cases that fall through the cracks of the automation, but they're nowhere to be found.
And it is going to get far, far worse.