I don't think that this applies to this very case though. Django was not made for Instagram, it was made available to the general public for free, as an open source framework. Instagram engineers only decided to use what was on the table.

I also believe that Instagram needs Django to be OSS, and the same goes for any other framework/language/library that other companies use, as OSS in itself is an extremely powerful label for a project. It brings together developers to form a community with lots of great minds and inputs. It helps feasible projects become production-ready and stable much faster than if it was closed source as its use-cases are far more wider than what a single company would provide.

Taking this from a competetive standpoint isn't very realistic in my opinion. I dare say that if either Django or Python weren't open source software, Instagram wouldn't be built on it in the first place.

I think it's absurd how Instagram can grow financially fat from the hard work of the Django Software Foundation without even contributing a dime to their fundraising or provide engineers exclusively to the DSF. IMHO Instagram should bring that fundraising up to at least 100%, considering Instagram revenue is estimated to hit $5.8 billion USD by 2020, $160,000 USD per year is a small price for the amount of value Django brings them.

It's a topic of morale though, Instagram does not owe the DSF anything, but I guess this shows where Instagrams appreciation lies.