Is Tenure totally worth it?

I was thinking about Tenure yesterday and how I probably won't get that for many years, which is scary! At the same time, is tenure all it's cracked up to be? I consider myself a great teacher, I take pride in my career, I care about my students, I go above and beyond the job description, and I always get my stuff accomplished. I have worked at a low income school under Program Improvement this past year and have had a real awakening to the world of tenure. As I received my pink-slip for the upcoming year I realized that there were other teachers at my school whose jobs were safe. And I know I shouldn't judge, but come on! A lot of the teachers at my school are jaded and take no pride in their job. There is one in particular who has no control over her class and hardly shows up to work, but she's safe. How is this possible, and how is this beneficial to our students? I understand the usefulness of tenure, but it does make it hard for us new teachers who are eager to get in, and stay in, a classroom for good reasons to get jobs. Any other industry, if an employee does not perform, they are terminated. How is it that a teacher can miss over 50 days of school, have nothing but complaints by students and parents, show no results on standardized tests still get to keep her job? This is a frustrating topic for me because I am now for the second summer in a row looking for a new job. It is scary not having job security, but at the same time those teachers that do have jobs should still be forced to perform. I'm not saying it should be based solely on standardized tests, because there are extenuating circumstances, but we give assessments, why shouldn't we be assessed?