The good news is most starting O lineman in this league (and some pretty good ones too) weren't taken in the first round. There's talent to be had in the 2nd round and later, you just need to have the scouting to find it and some luck on your side too.
WR on the other hand, you're going to find more the elite-type talent at the top. Not to say you can't find steals later because you most certainly can, but elite receivers are more of a premium.
We need both either way. We need to protect Josh and give him legit weapons to throw to besides Diggs.