Earlier quoted context omitted.
Definitely a blacksmith in almost every city, but probably fewer blacksmiths per city than the other jobs. Metal tools are built to last, and are expensive, so it was probably often a low volume high cost kind of business where production could be covered by a minimal number of smiths.
They must have been quite prolific then. There's a reason Smith is the most common surname in the English speaking world.
Similarly, Smith is a common surname because smiths, while relatively common, were rare enough that a given community was unlikely to have two with the same first name. There were almost certainly more shepherds than smiths in England when surnames started becoming heritable, but the surname Shepherd is less common.