Well, cannon didn't come all that cheap. And manhandling 1.5 metric tons of cannon and carriage anywhere is kinda demanding.

Didja know, in Gibraltar they actually had to come up with specially designed carriages so that the batteries located high up on that mountain thingy could depress enough to fire at ships close to the coastal fortifications ? Engravings I've seen about those suggest a forty-five-plus degree depression was achievable easily enough, and being coastal fortress artillery these would not have been very small cannon either...