When we launched WooCommerce back in 2011, WordPress only powered 13,1% of all websites online, but it has almost doubled that since then, and now powers a whopping 25% of all sites on the Internet.
I think open source generally grows stronger and more secure the more popular it is and more people it has working on it. We all benefit from a common platform we can build on and then differentiate on top of it, instead of reinventing the wheel over and over again for no good reason.
You can read more on Matt’s blog.