Everyone knew it was not the right fit. Now you have helped them move on to something they can do well, and really enjoy. I can never figure out why people stay at a company where they constantly complain, drag others down with them, are the root source of sometimes unfounded negative thinking, and have a hard time getting out of bed in the morning to come to work. How stupid to accept that. I love getting up every morning, and you should too.
Every new day is an exciting new opportunity to do something great.
Worse yet, good people will quietly leave due to lack of action in these areas, because they want to move forward, and don't see your company moving forward. Go back and think about some employees who have left in the recent past, and think if any might possibly fit this criteria. Let your team move your company forward. You are responsible for making it a good team. Configure it with the right people and empower them right, and give them the resources they need to help you help them.