So, they give off a scammy/idealistic dreamer vibe. Definitely doesn't feel like a "real" ag product.

However, there are some fellows in TX advertising a spray to harden caliche, which seems like it could be a similar product.

Is there anything knows which would help sandy soils retain water? I'm just working on adding a heck of a lost of compost and bio char to my back yard, but if I could add something else/something would work at an agricultural scale without running animals, I'd be interested.

we used a product in the oil field for water pits called Viper - it was kinda expensive but effective

https://viperproductsandservice.com/products/
the guys name was Zack Tuttle and lived near Lubbock

This sounds like the product you want:

https://www.siteone.com/en/089801-lesco-moisture-manager-hydretain-technology-granular-40-lb/p/336405

Though if it was me I'd continue applying compost every year to re-shape & build up your soil profile.
Much better long term IMO.

Snake oil is snake oil. Nothing you can buy in a jug will have enough of anything in it to alter your soil, unless you are putting it in a small container.