Yeah...I guess it sounds old school, but unlike other sayings like "offense wins games, defense wins Championships," it's still true.
You control the LOS with a really good OL and a really good DL, there's a floor to how bad you can be. You're going to be competitive if you can protect your QB and get after the passer/stop the run.
I don't think they took Morgan over say...Guyton because he's more NFL ready. I don't think that's how they approach the draft. You may be right, maybe they think he's a near lock to start at OG(which was a huge hole) and he has potential as a starting OT.
My guess would be they thought Morgan and Guyton had similar upside, but that Morgan had a higher floor and more certainty with his position versatility.