The concept of gods gaining their power from worship is a very modern one. Back in the day gods were, and had power, irrespective of worship.
In fact, from a pagan standpoint you don't even really worship gods. You might revere and honour them, but it was largely a transactional relationship. We give you these offerings, and in return you help us win this battle, or give us a good harvest.
There are in fact instances where after disasters or bad harvests offerings were actually withheld because it was felt that the god didn't hold up their end of the bargain.
There are two ways to gain godhood - or any power, really.
