People seem to think a root canal leaves a lifeless tooth. If true, wouldnt the tooth turn black?

When a tooth has a dental cavity, the dentist removes the "infected" area and seals it up. In a typical filling, the tooth is still very viable, having both blood flow and nerves throughout the remainder of the tooth.

A root canal is essentially a very extensive dental filling. Now both the pulp and the nerves are removed, and the tooth is sealed up. Because there is no blood flow into the sealed up tooth anymore, it could be considered lifeless. There is a chance the tooth could change color. However, when one has a root canal, the next step is to cover the tooth with a crown, so you do not see the "dead" lifeless tooth. Because the tooth has had much material removed, it is not as structurally sound and needs to be protected by a crown.

It can be a difficult decision as to whether or not one has a root canal or an extraction, followed by an implant. One thing most dentists indicate is that if you can keep the original tooth in your mouth, that is probably the best outcome. With my personal dental experience, I've had root canals, re-treated root canals, and an implant. With all that is involved in a dental implant, I'd happily take the root canal. Yes, there is some bone loss after a tooth is removed. Don't forget that implants are not 100%. Sure root canals aren't 100% either, but again, you are dealing with your original tooth. Cost of an extraction, implant, and crown is significantly more than a root canal and a crown. Also, time is an issue with an implant. Once a tooth is removed, nothing can be done in preparation for the implant for anywhere from 4 - 6 months.

It is considered to be a dead tooth, and there is a chance it will turn black, or at least change color.

You can still re-mineralize the outer layers (enamel) of a tooth with a root canal trough your saliva, but it will no longer receive anything trough the blood vessels in the root of the tooth.