I've been mounting behind plexi for 25 years, mostly large backlit transparencies for lightboxes. Without a clean room, by which I mean positive pressure, hepa filters, and an ionizer bar on the mount press, it's virtually impossible to get a perfect dust free mount consistently. On backlits, it's not a big issue because the dust virtually dissapears when the backlight is turned on. It's also on display in busy environments and is not exposed to the scrutiny of a fine art piece. That's why it's still commercially viable.
I do not offer this service to fine art customers because I don't think that without a large investment in a clean room, I can offer up the quality that they need.
Starting in 1985, and continuing until 1999, I did large volumes of C-printing, and over time, the prints have started to fade and degrade. It's happened to images on display, as well as those stored in archivel boxes (from Light Impressions). Nothing lasts forever.
My personal take on the plexi mounted prints is that I don't like the look, and prefer more traditional framing methods. And yes, I've seen plenty of Gursky's Dia Sec mounted C prints, and am not at all impressed by the quality of them. As far as Peter Lik's work goes, I've been to his gallery in Miami Beach many times, and consider a visit there the visual equivalent to spending an hour at the loudest rock concert in the world. I swear my eyes are bleeding by the time I'm outside. Yes, he's incredibly successfull, but the work is really very LOUD. Sorry for being an opinionated old guy, but maybe more effort needs to focused no producing great images, and less concern about how we mount them to slabs of plastic.