The old chef forged documents to take over the restaurant for himself, stealing from the protagonist, took advantage of the name Gustav to sell cheap food for profit.
He didn't forge documents. He just didn't want to tell the protagonist that he was the heir. I believe the letter also told him not to tell. So, in a way, he was fulfilling the dead mother's wishes on that.
Gustav's was failing. Selling cheap food for profit might have been the only way to keep the business afloat. Yes, he tarnishes the name, but sometimes things have to be done, and he might have had to make that hard decision.
This is why i love that movie, there's no evil person but one who doesn't want the restaurant to run by someone who can't even cook nor run a business, and he doesn't want the restaurant to shut down by health inspection. The crew quitting over it signified the seriousness of this issue. Linguini almost ruined the restaurant if not for Remy.
Also: Linguini did ruin the restaurant. Wasn't that kind of the point of the whole "Everyone can cook" idea?(i.e.: Haute-cuisine is not that important)
Nah. Confit byaldi is ludicrously haute-cuisine, needs three-star levels of manual prep work. The tag line is "Not everyone can be a great cook -- but a great cook can come from anywhere". And so can a good recipe or idea, that wasn't ever new in French cuisine it's been riffing off peasant recipes for ages, Escoffier did plenty of that.
Good food isn't special in the sense that everyone so inclined, with enough obsession, can learn to combine aroma, to cook things to point, all that stuff, which is how excellent home cooks are made. What sets haute cuisine apart is the time and labour invested in every dish for increasingly diminishing returns.
For that case we need to separate the two protagonists, Linguini and Remy. For the ending, i guess it's fair to say Linguini ruined the restaurant as he invited rats into his restaurant and to cook, but if we look at Remy as a separated entity, then the restaurant closed down due to Remy's and his family. The instance where Linguini almost ruined the restaurant is when a critic were served the same pot of soup he ruined, Remy saved the soup, thus saved the restaurant reputation.
Maybe I'm wrong but I always took it as a metaphor for class. At one point Skinner literally calls linguine a rat. Also Skinner wanted to turn the restaurant into a frozen food empire...
Idk if you had intelligent talking people-rats like in the movie then being excluded from whole industries just because people think they're icky would actually be pretty bigoted.