There's an industry wide argument over Natural Wine happening right now. Some people think Natural is the only real wine, others think it's a mass hysteria and it's all really crap, and more people are somewhere between.
First a definition: Natural Wine is usually taken to mean wine that is made from at the least organically farmed grapes, fermented with wild yeast on the grape skins, and then not manipulated with coloring, acidity, sugar, water, or other things added in the winery. Less than 10% of commercially available wines can make those claims.
Wine is such a personal and subjective thing, but that's never before stopped people from trying to argue over what's right or authentic. It's an interesting situation and dilemma. On one hand most changes and new movements are at some early stage a fad. The philosophy of natural wines in general is an extension or evolution of the desire for wines with terroir and sense of place, but taken a further and paired with a reaction against modern chemical technologic wine making methods. Natural, or maybe better called wild, wines have been around as a commercial movement for maybe 10 or so years, but it's just in the last 1 or 2 that the movement has gained enough momentum to break out of exclusively wine geek circles.
I don't think that I would call the Natural Wine movement as a whole a fad; however it may be experiencing a fad right now. If anything the arguments and attention are evidence of this. Louis Dressner was one of the first importers to go in this direction and Zev Rovine was one of the first to carry the terroir movement to it's more extreme elimination of chemical intervention and wild wine making extension, but the fact that now large established prestigious companies like T Edward wines are in the market is proof that it is no longer a niche and has crossed into the mainstream.
As with any new movement experiencing a surge in popularity and attention many new people will jump into the arena; they probably won't all last. It's rare for any business to last for decades. Market conditions (what people want to drink, exchange rates, what wine makers think people want to make) all constantly change and it's devilishly hard for a company to continually adapt.
As some people try to challenge the legitimacy of natural wine making it's good to remember too that natural wine making is unusual in that it started from the supply side. The movement started with wine makers who were fed up with modern conventional wine making and decided that it was worth risking their livelihoods to experiment with something new and unknown. That's how bad wine making with pesticides and chemical fertilizers had gotten; natural wine wasn't originally created to sell wine. Natural wine making started as an uprising against the status quo.
Natural wine is a new development and as such many winemakers are self-taught. Self taught only happens with mistakes. I'll be the first to admit that there are many flawed examples out there; however there are also people making really transcendent compelling wines from this method. Natural Wine is a new thing that is still developing and defining itself, but I'm sure that this type of wine is here to stay. The Natural Wine movement has a lot of value for the wine industry in reminding people that wines are living fragile agricultural products.