Well the Jags spent just enough to keep Bortles there as a high priced bridge which will probably be like the Cardinals in free agency... you cannot tell me the Jags think "that's our guy"
I think the Jags made an investment in him and want to continue to surround him with talent and support him, rather than just dump him. His accuracy was up and his turnovers were down this year and they did win 2 playoff games with him at the helm. I can see why people would think they should move on but I can also see why the Jags don't want to upset the apple cart. I assume they want to see what Bortles can do now that he has a running game and when he gets Hurns and Robinson back.
As pedestrian as his numbers were this year, I think it's important to remember that he lost his WR1 and WR2 and they went without a stud TE. Thomas was a disappointment but 33 year old Lewis wasn't even a replacement for that.
Bortles' accuracy still needs to improve(somehow) but I do think he's maturing and improving overall. Maybe his 37 TD season a couple of years ago was a fluke but I wouldn't be too quick to give up on a guy who's always on the field and just won 2 playoff games who can produce at that level.