I believe Lovie was enticed to take the job with a promise that he would have the time and resources necessary to succeed. I'm guessing that Josh's pitch to Lovie was basically, "Build your legacy here. Show the world that the Lovie way to football is a winning way to football." A place where he can make all the decisions and build the program the right way.
Lovie 100% understands that some of his hires were not able to execute his vision, and now there isn't time to get staff wrong again. A failure at DC is the end of the Lovie Football Legacy dream.
So why is it taking so long? I suspect it's because Lovie wants his new DC to be the best possible fit for the challenge and conditions. And given how successful and non-traditional the recruiting season has been, I'm perfectly okay with Lovie taking a non-traditional approach to these hires, too. He may want the DC on board before pulling the trigger for hiring the position coaches, too, to ensure they're all on the same sheet.
In Lovie I (continue to) trust. <Crosses fingers>