You’re correct. Take Drew Breese for example. An outstanding QB, but without the needed protection he becomes erratic and prone to making mistakes. Couple that with a defense incapable of containing the opposition’s offense and more games will be lost then won as evidenced by the Saint’s 7-9 season.
You build a team around an offensive line.
If I were a GM, my first priority would be to get me the best damned offensive line coach money can buy who can take a ragtag bunch of journeyman offensive linemen and turn them into a solid unit.