If you own the premium pass, it will be available for two seasons and be known as a "legacy pass" during it's second season. After the second season ends, it will lock permanently. They also mentioned that they're increasing the earnable SVB to 500 in S2. Still not enough to unlock the S3 pass, but it's at least half which is... acceptable, I suppose.
As far as not earning enough Tix during S1, you seem really far off for playing as much as you did. Though I will say even for those who were able to complete the pass still cut it super close. I completed every daily task of S1 (with the exception of 2 days), completed every Tix quest on the map including co-op missions, claimed every Seasonal/weekly quest and completion bonus, 100% completed both events, claimed every daily Extravert gift, claimed the 2000 Tix gift, and still only finished the S1 pass a week ahead of time. The fact that you are almost 9000 Tix short is really odd.