I have worked for startups (Seamless.com. Quirky.com, Skillbridge.co) and I have made films (Amanda Knox, EuroTrump, and Freedom For The Wolf). There are many similarities about these environments and many differences too. Here's some high level analysis on this topic: 

Similarities: 

1. A high failure rate: Today there are about 10,000 films made per year. Less than 10% of these films will get released in US cinemas; in 2016 the figure was 736. And about 100 of these films will be studio films from Warner Bros, Disney, Fox, Paramount, Sony and Universal. While this may seem like a lot, there are 1 million new businesses created every year. Of these businesses, about 50,000 in the United States raise funding from angel investors. But most films and most businesses will be destined to failure. In the indy film world, you are up against major odds. As Stephen Follows writes, "Over the past ten years, 74% of all the money collected at the UK box office has gone to the top 50 grossing films."

2. Dreamy-eyed people dominate the industry: In an era since Mark Zuckerberg first turned tech stars into rock stars, the tech industry has been dominated by dreamy-eyed people imagining Maseratis, private jets, bottles of Dom Perignon, and boating on the French riviera. This was already how most people felt about the film industry. As such, any industry with bling at the end of the rainbow will attract tons of hangers on, talentless people, and wannabes. 

3. You can bootstrap a startup or a film, and it's getting easier: Good news for the film world. You can buy an amazing $2,000 camera, $2,000 worth of lenses, and $500 worth of sound equipment and bing, bang, boom, you're in business to make a movie. And luckily, most Directors of Photography have already made this investment so it won't fall on you as a director or producer to make such a purchase. In the startup world, tools from Squarespace, Gmail For Work, and even Salesforce can now be modified to fit the "solopreneur" budget. 

Differences: 

1. At startups, the sky's the limit; with a film, you have limited upside: This is the most important difference between startups and films. Let's say you make an excellent indie film on a $1 million budget. You may sell it to Netflix in perpetuity (forever!) for $2 million. After you pay your sales agent (15%) of this fee, you're netting $700,000. And let's say you have you only had one private investor in this film who gets 50% of profits. That leaves you with $350,000. But let's also say you as the producer and the director are equally splitting this upside. That's $175,000 each. And finally, say sayonara to 50% of that money because it's going to the tax man. So, at the end of the day, you've netted yourself less than $100,000. However quite frequently, you will also have to pay out other investors, producers, or people working for your film who benefit from the upside. Sorry Charlie, but this is the harsh reality of indie film. 

However in the startup world, if you're decently successful you'll get acquired by a bigger company, and if you're extremely successful, you'll stay private and make a load of cash or go public and make even more cash. 

2. Startups are much more likely to attract heaps of investment: Some 50,000 startups each year receive "angel" funding in the US. This could be $50,000 or it could be $50,000. Either way, there's a heckuva lot more money being invested into independent startups than there is into independent films. 

3. In a startup you can pivot, in a film you cannot: The word "pivot," now frequently parodied on shows like Silicon Valley, is a very real thing, and startups do this frequently. For example, I have a friend who started an online retail company to compete with Etsy. After working on this for a couple of years, she realized that the advertising technology she had built was far more interesting than the store itself. 

Whether you are making a documentary or making a feature film, it is insanely challenging to make a true "pivot" once your project is underway. In a feature film, it is near impossible. And in documentary, if you are going to call it a "pivot" you might as well just say you are starting to make a film on an entirely different topic and not using any of the footage that you've already shot. This said, one example of a successful pivot in documentary is Bryan Fogel's film, Icarus, now on Netflix (an excellent watch!). In Icarus, Bryan starts off his film by trying to use illegal doping mechanisms to give himself Lance Armstrong-like superpowers. Ultimately he "pivots" and reveals a much larger cheating scandal leading all the way up to Vladimir Putin. Of course there's a bit of timing and luck involved with this pivot, but Bryan capitalized on it very well. This said, unless you "pivot" at the start of your documentary, chances are you are then wasting a ton of time that you will never get back.