30-yr mortgage or 100-year mortgage + invest the difference?

Hey friends,

I've been thinking about those wild "100-year mortgage" ideas floating around (yep, multi-generational loans that could let your grandkids finish paying off your house!) – especially since housing affordability and crazy-long loan proposals have been in the news lately. I asked Grok to model it for a $500k house, and whoa, the debate is intense:

The "100-year mortgage + invest the difference" strategy sounds almost too good to be true:

Insanely low monthly payments (like ~$2,688 vs. $4,286 for a 15-year).

Invest the huge $1,598/month "savings" in stocks.

If stocks return 10–12% and your house appreciates even modestly, you could end up with MILLIONS more after 30 years thanks to compounding + massive leverage (the house grows while you barely touch the principal).

BUT the risks are massive – this is why almost no one actually offers 100-year loans in the US:

After 30 years, you still owe almost the full $500k! You've built basically zero equity.

Stocks can tank or just average 5–7% → you lose big and pay a fortune in extra interest.

If home prices stay flat or crash, you're underwater forever and the leverage destroys you.

Life hits hard: job loss, emergencies, or just spending the "extra" cash instead of investing it.

You're stuck with payments for literally a century – into retirement or even passing debt to your kids. No peace of mind!

Grok's verdict: In perfect bull markets with strong returns and rising home values, the 100-year strategy crushes it mathematically. But for real people? It's super high-risk gambling. Dave Ramsey would lose his mind – he'd say pay it off in 15 years max and live debt-free!

What do you think – would you ever consider a 100-year mortgage to try getting rich off the spread, or is that straight-up insane? Team leverage or team debt-free ASAP?