Walt, I know you don't want to hear it, but that fort-knox level copy/editing protection is to try to head off cheating. It's probably also there to limit modding, as they want to sell expansions and whatnot, but it's mostly there to try to curb cheaters. Microsoft was cagey about bringing their Xbox games to PC, because they were worried about the fairness in multiplayer. I'm not sure if the Steam version of Halo Infinite has the same protections, because apparently HI has a lot of cheating issues currently. I'd be interested to see if that's the Windows Store version, or the Steam one, or both.
Anyway, as for demos, well, Extra Credits did a video on this years ago.https://www.youtube.com/watch?v=7QM6LoaqEnY
Basically, demos cost time and money to make, and rarely have any beneficial effect on sales. Refund policies on digital storefronts make demos irrelevant-ish...it doesn't help if a game has a slow-as-mud intro that makes you quit before it gets its hooks in. I'm looking at you, Divinity 2.