This is a very good question and I actually like the idea of the three-strike felony law. Naturally, certain felonies should be automatic life in prison, such as murder, but something like grand theft, or drug charges, yes, I think if someone is caught three consecutive times with the same changes; life in prison.
After committing two felonies, a person should know that they have a problem that needs special attention. In fact, a two-strike felony law wouldn't be unreasonable, depending on the crime. We already have one-strike felony laws such as murdering a police officer. If the criminal isn't shot dead in the streets by other officers, it's usually a swift court case to put the person away for life.
The three strikes law needs some overhauling. The way it's written now, a person gets three strikes of any combination felony and misdemeanor and they go to prison for the rest of their life. Think about this -- if you did one or two really bad things in your life that you regretted, and then 30 years later a cop pops you for jaywalking and your freedom is taken away forever. Do you think that's right, because I don't.
Felonies are very serious crimes, I understand that sometimes a person can be charged and convicted of a felony when they are a good person so one or two mistakes should not be counted against them permanently in life, however after a person receives a third strike it shows they have no care. There is no reason to have 3 felonies, it is no longer a misunderstanding or mistake and the person should be fully punished.
I don't think there should be a three-strike felony law because felonies come in all shapes and sizes. I think every case should be evaluated separately and the prison time give should fit the crime. A one size fits all approach to the legal system is never a good idea.