If the worry is the OL holding up and Fields being forced to play behind a bad OL, then if the OL can't hold up, it will eventually end with Fields being forced to play behind a bad OL.
This is the same logic that a team without a QB should wait until they have the perfect situation before they draft a QB. Don't get me wrong, OL is very important for team success. But the ultimate success is dependent on the QB. The Bears went 8-8 back-to-back with a below average OL because of the QB. A good QB and they win a lot more games, despite the OL everyone hated.
Also, you guys overstate an OL getting "destroyed". This isn't something that happens very often. David Carr's OL got destroyed. Jay Cutler's OL got destroyed by the Giants in the 9 sack 1st half game, and then they adjusted to just be terrible. The Eagles OL was probably pretty close to destroyed this year. We complained about the Bears OL for years, but they were still not terrible and nowhere near "destroyed". They added talent, got healthy and gained experience....yet somehow all of a sudden are not going to be able to hold up to the point they get people injured?