1) Lawyers are not held to account. They mislead other lawyers and the court and they're allowed to do it. Disciplinary boards are toothless and only go after small practitioners - never the larger firms, unless they REALLY screw it up. Sole practitioners and two/three man law firms, they're easy targets because they don't have clout, so occasionally they'll string one of them up, but if you're a partner in a large law firm, you can do and say pretty much whatever you want, even if it's totally misleading. And a a lawyer, you can't call the other side out on it without proof, because that's professional misconduct. So even though it's blatantly obvious to everyone what's happening, it goes on. There needs to be tighter restrictions on how lawyers act.
2) Because the system is abused. Firms reward by the highest biller, not by the skill of the lawyer. Lawyers are encouraged to bill maximum hours, which means that they falsify time sheets, spend far longer on tasks than they should - they milk everything out of it that they can. What other professions charge by time? Dentists, doctors, teachers, vets - all charge by task, not time. Accountants and lawyers are by time.... and both professions milk it :P
3) Discovery refers to the process of exchanging documents between two parties in a civil trial. What large companies do when they're against a small fry is dump thousands and thousands of documents on them, completely irrelevant crap, and mix in the important documents in with that. It then falls to the small guy's lawyers/the small guy himself to spend hundreds of hours poring over useless documents to try to find any speck of relevance. It's like trying to find a needle in a haystack. Discovery should not be as expensive and time-consuming as it is - courts should take more control over the process and punish parties who abuse it. And believe me, they abuse it.
Like I said... I could go on :P