On the contrary, I’ve found that companies who are actually doing hardcore software engineering, where the code is the main value driver for the business, rarely open source their best stuff, but they’re great places for engineers. Google doesn’t open source its self driving car code. Facebook’s value driver is the network, not the code, so it can open source anything. Dropbox’s client is amazing and is not only clos…
Seriously, the Dropbox client? I mean, I never used it but I can hardly imagine anything that makes it so special. I use Nextcloud and from what I can tell, there is nothing that sets the Dropbox client apart from the Nextcloud sync client (which is 100% open source). In addition, some parts of the Dropbox sync client are open source too: https://www.dropbox.com/de/help/desktop-web/linux-commands#b... Sure if your bu…
Writing a simple file sync utility isn't difficult, hell you could just wrap rsync and you'd be half way there. Making that open source is easy and low risk, because you haven't really invented anything.
On the other hand, if you can throw 100 developers at the problem, you'll come up with something _far_ beyond the simple case. Sure it might only be 50% faster? But that 50% makes your product "magic" when compared with other tools. This is where you get things like Project Infinite (https://blogs.dropbox.com/tech/2016/05/going-deeper-with-pro...). I can imagine there are some very complex optimisations for the multitude of configurations that Dropbox runs on, that I can understand a company wanting to keep "secret" if it's so core to their business.
I think you'd be surprised at the depth to which these companies are solving problems.