But 20% of $200k/yr is $40k/yr, while 20% of $100k/yr is $20k/yr. If you make twice as much while saving the same rate (i.e. cost of living goes up proportionally), you'll still end up saving twice as fast. Then move to a LCOL area, and you've got twice as much saved as the people who've lived there all their lives.
Yep - this is what a lot of people who suggest moving to a cheaper area as a solution for not being able to buy a house don't seem to think about.
Earning (made up numbers because I don't even live in the USA and I don't know what is reasonable) $100k and spending half of it on rent with no hope of buying a house is still better than earning $50k in an area with much cheaper housing.
Of course if you can score a remote job then you can have the best of both worlds, but that isn't always possible (and some companies seem to pay differently based on your COL now).
I think it's a pretty big unsourced assumption that savings rates are similar between LCOL and HCOL areas. I'm curious if that's really true; I wonder if there's any research/polling done on this.