No. There is a reason you are limited to $10k a year. I bonds are not a financial product being sold for the benefit of the seller. They are a government service being provided for the benefit of the buyer.
EDIT: Thanks for the replies. TIL.
There's some rules on if you cash out before 5 years (you give up the last 3 months of interest) and you MUST hold for 12 months.
You can ladder them too and have different amounts / times of purchase.
I like it for planned emergency funds that would otherwise be cash, ladder into it so you always have your EF available.
https://www.thebalance.com/tax-advantages-of-series-i-saving...
1) No state tax on I-bonds
2) You can defer and pay tax on the interest only when you sell the bonds (which means you can time the sale to when you have lower income)
> or do they retain the 8% for however long you hold the bond?
No, the interest rate is updated every 6 months, see the sibling comment.
As the parent comment stated - this isn't meant to get anyone rich. This is the government providing a service that allows (working-class) individuals to keep a rainy-day fund relatively insulated from risk. If you're able to save more than 10k per year, you're not the primary target for this service.