If Entrepreneur mortality is a function of execution speed, then certainly it should not take 5 years to realise, one is stagnating. It should not take, even 5 weeks in fact.
I am not sure, what is your definition of "street smart", but in my opinion it is "common sense".
There are various genres of entrepreneurs and learning curves for each is different, for some it could be long and difficult.
But that is what the whole package is all about. When we sign up for the package, we sign up for all the parts, and not the beautiful ones only.
The mortality rate is 99% because of "Hubris".
Everyone is thinking that, that they are changing the world, denting the universe, rocking the stars and when it is time to get customers, they find it hard to get even one, because the problem that they were solving was the figment of imagination of their own mind. The problem was never their in the customer's mind.
Someone great has said, "Make something, people want". You do this and you are almost immortal.
But say, you make something which people want, but still die due to money,family,illness,girlfriend whatever...
Take another shot, as someone great said, "You have to be right only once".