[ivanhoe]

Depends on the area of expertise we're talking about. In sport amateurs absolutely can be as good or better than professional athletes. Musician or painter or programmer, same thing. But a skilled worker in jobs that are all about practice and experience? For instance I can manage to lay a brick wall or put tiles on the wall, but I did it only a few times in my life and I doubt that anyone not doing it professionally can have a significantly more experience than that - you just don't get a chance to do a lot of DIY projects like that - while someone who does that professionally is doing it for many hours a day, every day. That makes a HUGE difference in experience and that translates into the quality and speed. As DIY amateur, even if you come close in the quality, it will certainly take you 10x more time than professional.