[DannyBee]

"Sometimes you need to let talented engineers build things from the ground up, because it's good for them, makes them happy, and stops them from going to work somewhere else. "

actually, trying to let people do work you don't need done, in order to keep them happy, is a pretty rookie manager mistake.

If they aren't passionate about it, and you can't persuade them to do the things you need doing, they aren't the right person for the job.

That is always true, even if they were the right person in the past.

Your goal in that case should be to try find stuff the company needs done that they want to do, and push them to work on that. But if you find nothing, ...