Okay, according to this article[1], you need a "nest egg" of $2 million to have a retirement income of $80k per year. In 2021[2] the median household income was about $70k. The average household size[3] in the US is currently around 2.5 people, so let's round this up to 3. The poverty line[4] for a 3 person household in 2022 is roughly $23k, for 2 people it's roughly $18k.
Let's say we want a nest egg allowing a two-person household to have a retirement income of $60k: quite a bit below the median household income in the US but still considerably above the poverty line, a net positive considering you don't need to work for a living as long as you don't plan for either one of you to live for more than 30 years.
$60k is 75% of $80k, so that nest egg shrinks down to a mere $1.5 million dollars. But you should aim to live on 80% of your pre-retirement salary, so your pre-retirement salary should therefore have been $75k. In order to get there you need to set aside 15% of that $75k household salary (including any 401(k)s) every year, or just shy of $12k, leaving you with $62k actual income after retirement savings or $5.2k per month for the household (you, your spouse, any children, rent, cost of living and savings for emergencies like health, maintenance or replacements).
If that doesn't sound so bad, consider that this is for someone living just above the median and aiming to maintain a similar standard of living. The further your household income is below the median, the more painful those 15% will be and the only reward will be to get to live in the same level of distress just with a more reliable stable income (assuming it doesn't get eaten up by other expenses you couldn't save for or that arise as a consequence of your already low standard of living, e.g. health issues).
So if that's the "best case" prospect, can you imagine why the chance to become a "millionaire" (and remember: a $2 million nest egg represents a $80k retirement income, a good $10k above the median household income) might be more enticing to a significant chunk of the population than the safer more reliable investments that will at best help them maintain their meager standard of living as long as they don't have any unforseen emergencies?
The exact numbers here are entirely irrelevant. Jobs with higher income generally also offer better options for investment and retirement plans, jobs with low income may not even offer a 401(k). Low income also means any expense represents a larger percentage of your income because costs don't scale linearly, especially when it comes to essentials (e.g. gas prices are the same for everyone and a cheap car may actually get worse mileage and require more frequent repairs compared to a newer model that may still be in warranty).
[1]: https://www.investopedia.com/retirement/how-much-you-should-...
[2]: https://www.census.gov/library/publications/2022/demo/p60-27...
[3]: https://www.statista.com/statistics/183648/average-size-of-h...
[4]: https://aspe.hhs.gov/topics/poverty-economic-mobility/povert...