When I first played Red Alert, it was on a computer with a 6.4GB hard drive, and I had no idea how to fill up that much space at the time. I think we’ll be fine.
Correct. The license (at least, the one I read for Red Alert) is GPLv3 with some additional stuff. The additional stuff is mostly about not using EA trademarks in your version or showing any connection to EA itself. So it appears that a clean room asset swap would be allowed as long as it includes the title screen.
Linux, not Windows–Windows provides little that can’t be done on Linux in this space
AMD, not Intel–AMD just has better products at this level (any level at this point, really)
720p–going higher doesn’t provide much at this size except suck battery life and requiring a more powerful GPU
Price
Now, price is partially because Valve can afford to subsidize the cost and expect to make it up on Steam sales. I’d be remiss to ignore how they’re making their money. Still, they’re also able to have a good price because they didn’t try to make it as powerful as it could be, but as powerful as it needed to be.
The techniques you’re thinking of are for documents sent by email or some such. You add innocuous whitespace or typos that are unique to each one, and send them individually. If one leaks, you can match it to the employee who received it. That doesn’t work for screenshots of Slack.