lilac bush did not bloom this year
Bush appears healthy and much larger than last year. It has full sun in fairly rich soil. It is about seven feet tall and I have not fertilized it.
There could be a few reasons for your lilac not blooming.
My best guess would be it does need a rejuvenation prune. I did this very prune to our lilac when we moved to our home. The lilac was only producing a few flowers. A good prune and 2 years brought a tree full of fragrant blossoms.