There may well be too many foxes in town- but the real culprits are thos who a/leave rubbish for them to feed on and b/ those who feed them and encourage them to multiply. Foxes are actually really good at controlling their own numbers. When food is scarce, only the head vixens will breed, and have 1 or 2 cubs. If food is plentyfull they will all breed and have many cubs. Very well studied and reported by Bristol University over 40 + years.
In the countryside, foxes are THE ONLY predator for rabbits and all sorts of vermin- they do a splendid job. Eliminate the foxes and you will see vermin of every kind multiply. If they were not fed by rubbish and food left for them in town, they would soon get rid of the massive rat population and other vermin we have.
Foxes do have a very important rôle to play in a country with no other predators (well badgers will take litters of rabbits and rats, etc- but never to the same extent as foxes).