6 months post op septoplasty and I have worse breathing than before surgery. Considered failed? What are my options?

It is hard to determine what you or the second surgeon mean by a 50 percent blocked nose or an 80 percent blocked nose as this is not proper medical terminology for a nasal evaluation.  How would this doctor even know what you started with having never met you prior to your surgery?  I would seek consultation with a board certified facial plastic surgeon.

Hello,You are correct, if your nasal airflow was better early in recovery, when swelling was worse, than this problem you have is not due to swelling. Unfortunately, the most effective and predictable way to perform this surgery, open structural rhinoplasty using multiple grafts to re-establish structural integrity, is not commonly or correctly performed. You'll need to visit a revision rhinoplasty surgeon to evaluate not only static structural blockage, but also dynamic issues that you may have (swelling actually creates structural rigidity, keeping airways open). 

it isn’t clear the extent of surgery you had done, specifically with regard to narrowing the nose.  Obviously an examination would be necessary to determine exactly what is causing breathing problems.  A possibility is that you have enlarged turbinates that were not addressed.  If so there are ways to reduce the turbinates that are quite simple and reliable.  I reduce turbinates  in most rhinoplasties I perform.  It can even be done in the office using a radio frequency device.  Worth checking into.