Well they did attempt to fix the O-line in the past, the problem was several of the players drafted just didn't pan out. I believe the players drafted more recently may work out, they showed improvement as the year went on last year. You have to give them time to adjust, especially with no preseason.
The last quarter of the season, Hunt was doing very well at RT. 3 rookies at once is bound to be a rough ride but they protected the QBs pretty well until the last few games. Coincidentally or not, we opened up no running lanes all year until the last few games when our QB coverage suffered.
Whether we draft another O-Linemen or not, I would expect the line to continue to improve.