Official transcripts are available, usually, but the transcriptionists are private contractors rather than employees of the court, and are hired by one or both sides to create a record of the trial for appeal - essentially the attorneys are outsourcing that bit. Most documents in a court case are easily accessible online at moderate cost (typically ~$0.08 per page, to cover the cost of hosting) but transcripts can be insanely expensive, running into the hundreds or thousands of dollars. It's a bit of a racket to be honest, but court-employed transcriptionists would either raise the cost of filing in court or require more taxes, and legislatures keep courts on pretty tight budgets.

I don't like the idea of court video that much...bad memories of the OJ trial.