Of course it can be replicated without MSG. Most of it has been made without MSG since inception, even those that aren't Asian at all.
Lots of MSG sucks, because the base flavor just isn't there. Browned bland food tastes like burnt bland food...not much of an improvement. No MSG is fine. A bit of MSG is fine. Personally, I prefer places that don't use MSG, but I'd bet that if they added some, they'd still be better (IE, they're making a point of not using it because they're proud of their food's quality, not because a little MSG would ruin it).
Now, gluten...well, of course you can't, because some sauces need it, as do noodles and wrappers, for staying together and having the right texture. Faking it never works right, but some people would rather have bad fakes with poor texture and flavor than just learn to eat good food that doesn't need it (much like meat substitutes).
From the article, what I most get is one more reason I don't think I would want to live in California. Those customers seem like douchey stereotypes, along with some of the anti-restaurant-owner commenters;
and if there are a ton of Chinese places, that aren't sit-down dinner type places, making a point of not using MSG and/or Gluten, there are clearly
way too many deluded assholes per square mile.