The general concept you’re describing is called Risk Compensation. It feels intuitively correct, but in whatever context it’s been studied in almost all cases it turns out that the safety feature is actually better overall. Some people might be a bit riskier knowing about the safety net, but not enough to counteract the safety improvement.
Also - in the UK - road deaths go down over time, while miles driven goes up. Driving is getting safer. Cars are part of that, but so is road nd signal design and driver training.