The people that are DL's are probably just wired for it. That's not to say that a certain percentage of the populus wouldn't derive some kind of anxiety reducing effect if they could try them without the negative social consequences.
From the outside it all looks like a sexual fetish and that's a really big hurdle. "BTW I know you think that grown men/women that WANT to wear diapers may look like a sexual kink, but you should try it and see if your anxiety goes down".
From the inside it can seem so innocent and fun. However because it crosses the line into sexual fetish it will probably never be fully accepted as a potential for relieving stress and anxiety.
But..... I wish everyone could at least try them in a consequence free environment just once. It would probably change people's minds. However it's probably naive to think that others could derive the same kind of pleasure or satisfaction from the diapers as some of us DL's do. Because there just not wired for it.
Just saying...