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.
“In the discovery of secret things and in the investigation of hidden causes, stronger reasons are obtained from sure experiments and demonstrated arguments than from probable conjectures and the opinions of philosophical speculators of the common sort.”