An 18 year old isn't getting a mortgage. They probably won't be able to afford a home for the next 7 years anyway. They might have a rough time getting a reasonable car loan and opt to instead buy a used car with cash, but that isn't the end of the world.

Making a high risk play and maybe going bankrupt at 18 might even be a dominant strategy.

I never used credit from 18-25 aside from churning some credit cards.

It sounds to me like this is the dominant strategy for many people who dont use the traditional credit system much and are young and have no assets. You get a 1 in 20 chance of a million dollars and in 19 of 20 cases you go bankrupt. Seems like a extremely +EV deal.

Not only not the end of the world, it’s a much more sound financial move :-).

Prime mortgages hover around ~3-4.5% currently. Non-QM is ~5.5-8 percent, looking at a non-QM lender's rate sheet right now (dependent on loan to value, assets, and income). So about what you'd pay for a HELOC or higher rate home equity loan. Even with garbage credit you're not paying 9% on a property that you've got some equity in, but you're not getting a mortgage with only 3% down (nor should you; go rent for a year or two with a landlord who will report positive payment activity to CRAs and then go get your federally backed FHA loan with only 3% down).

I was just using 6 & 9 as example values from the ether (maybe Hendrix) - not in reference to any specific loan type.

And yes, Prime is low today.

Also, if you can make a play for real property: buy dirt. It's a good financial play to build equity/wealth.