No single mechanic ever implemented is "hard" on its own. It's the combination of many happening at once and also requiring high throughput.
The topic of course is the degree of punishment for failure, and indeed having mistakes be punished with wipes makes clearing an encounter much more difficult than just it killing 1 person. It's pretty much one of the only ways Blizzard has been able to challenge the very top end guilds because their skill level is so high.
Your car anology is stupid when compared to a video game where you are intended to fail many times before achieving success.