> With enough time, any sufficiently large company can implement their own version of any software that anyone else has written. They usually won't write their own version if a high quality opensource version exists with a permissible license.

Is this a true assertion? If you define sufficiently large company to be Google, Microsoft, Amazon, etc. then sure, of course they can. That's an extremely high bar though and I would bet that even then, these companies would have to pick and choose their battles.