The short-term risks of taking Plan B repeatedly are mostly amplification of the known side effects. The long-term risks are unknown. But some emergency contraceptives aren't hormone-based at all. Ella is made of some sort of acetate, I believe. No one has any idea what the consequences of that are when abused, either.
Yes, there are people who do this, just like there's people who abuse anything.
I'm glad your experience has been relatively problem-free. However, that has not been the case for all of us. A very large minority of women have unacceptable or severe side-effects from BC. It should absolutely continue to be prescribed by a doctor.
You can go to Planned Parenthood and get your consultation and prescription on a sliding scale. Free, if you have either your own insurance, their coverage, or are under a certain earning bracket. It's not as though it's incredibly difficult.