Because not enough people have died for anybody to really care about it. It's all about money...At least in the US
If a TV or screen is on the front dashboard so the driver can watch it, it is illegal. At least it is here. In some places you can't drive and talk on a cell phone, but it is city specific just like TV.
It's illegal in Oregon to have DVD player in the front.
It is illegal in Tejas.
I think that it is illegal in MA
I've seen lots of dashboards with TVs, in MA.
that doesn't mean that it is legal.