I think this might be a tad of an overreaction if I may. There are still other o-line available in FA and one LG does not a SB make. Luck's health is the be all and end all when it comes to setting expectations next year.
As for the Jags, sure they have a great Defense, but it has been exposed in games. They also have hitched themselves to Bortles, problem being it's the team pulling him along not the other way around. The run heavy P/A stunt they pulled last was a great Davids strategy but won't be sustainable in the long term. I mean just look at the 2012 season sponsored by read option overreaction. Teams have film now, they will adapt and target him.
The NFL has been, always will be, a QB driven league. If ours is healthy we still have that over the Jags.