I know this is a troll, but I'll bite.
For most average people, there are absolutely times when a lawyer is valuable, but sometimes it is just gatekeeping. Most people with uncomplicated financial situations could write an OK will. Lots of small disputes can be handled in small claims court without lawyers. Generally, stuff that is non-adversarial shouldn't require an attorney in an ideal world.
However, for anything criminal defense, an attorney is a must. The criminal system is structured so that you would have to be an idiot to go at it alone.
For businesses, the calculus is very different. Just hire the expert (an attorney) to handle things and focus on making money in the business.