HUD symbology is focused at infinity, so there's no 'background'. The symbols and the real world are at the same hyperfocal point.

Fighter pilots have been using HUDs for 70 years and in the past 20 years they have become common in airliners as they hugely improve safety in low-visibility operations.

You might reconsider that opinion when you get old. When you cannot see well at short distances, it's difficult to see the writing on the monitor, so the HUD navigation really helps.

You’re just straight out incorrect. The HUD doesn’t obscure vision, and if adjusted correctly for position allows you to keep your eyes closer to the horizon while maintaining awareness of important information.

It’s the best thing about my new car and I can’t imagine buying something, other than a track beater, without it in the future.

The HUD is order qualifying for me now. I’ve had it in four BMWs, and if I had to do without gauges (which I don’t, because that is idiotic), the only acceptable substitute would be an HUD.