Because &#x27;economics&#x27;.  Switching costs, network effects, etc...<p>Here&#x27;s my favorite book on the subject: <a href="http:&#x2F;&#x2F;amzn.to&#x2F;1JMtX0X" rel="nofollow">http:&#x2F;&#x2F;amzn.to&#x2F;1JMtX0X</a><p>And yes, that&#x27;s an affiliate link: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10982630" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=10982630</a><p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Switching_barriers" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Switching_barriers</a><p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Network_effect" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Network_effect</a>