Have diesels lost all reputation for reliability?

I'm in the market for a half or 3/4 ton truck and I've found some really good deals on lower mileage diesels in both categories. In research, I've basically read that every newer diesel engine across all brands and all sizes come with an incredible amount of frequent, known issues. When I was a kid in the 90s, diesel automatically meant 500k miles. I know there's a bunch more going on with emissions regulation nowadays. But is that the only reason we're seeing these issues on the new ones?