I am a quick study - I can memorize a script in an hour - but I can't remember a name three seconds. I've even forgotten my wife's name on occasion.
In Irish law, busking is considered vagrancy - you can be arrested for it. It's risky asking people for money in public. So it's not like it's a high-art job. And people who do it as a high-art job make very little money.
I guess the bigger you dream, the further you have to fall if you don't get it, so it can be a bit of a scary thing to be that ambitious.