Over at Joomlashack, we’ve hit on a business model that is working well.
Oh, and we’ve adopted WordPress plugins too with Bylines and UpStream.
Joomla and WordPress are mature markets and some developers are leaving after 10+ years. We think that adopting code is a win for everyone. In the past, developers had limited options if they wanted to stop work on their extensions. If they made an official announcement, they had to deal with unhappy users. To avoid this, sometimes the developers would just disappear. In contrast, a smooth adoption leads to a great outcome for the developers and users.
I suspect we’ll adopt more Joomla extensions in the future, and more WordPress plugins too.
Update: We did indeed adopt more. See this post on going from 1,000 to 100,000 WordPress installs.