The Guy Who Lost 8,000 BTC. Could He Have Done This Instead?

I saw a British TV show on YouTube on guy who lost 8,000 BTC in the landfill. In the show they quickly showed his computer and his address with the 8,000 BTC. It is at 4:10 in the video.

https://www.youtube.com/watch?v=cZr97E5PgzQ&t=232s

I realized it was the same address discussed in this YouTube video below from 5 years ago where the poster was wondering who in the world mined 8,000 BTC and had not touched it. This is that video...

https://www.youtube.com/watch?v=9G3Sz3LbEUM&t=293s

In the first video it appears he was keeping his keys on a single EXTERNAL hard drive? I have three questions....

1. Did many people mine coins back then on external drives? Or on their main computer drive and then save a backup on an external drive?
2. If someone wanted to mine for a year back then, if one had a proper backup (which he clearly did not) then would it have been just as safe to mine on one drive or would it have been wiser to use different drives and completely different addresses?
3. In 2009-2010, was there any malware stealing keys off people's drives or because BTC had no real value, that had not begun yet?

Thanks!