Are we still debating things on a universal basis ?
Because there are a number of problems with this argument (and I think you meant Zeus, not Thor who is the god of thunder...???)
1) It assumes an agreement on which god lightning is/was an act of. There could be dozens of gods used to explain lighting from Aztec gods, to Hindu gods, Shinto gods, Finnish mythologies, African tribes and so on....
So universal agreement on which god?
2) Some of these people still believe in this day-and-age that lightning can be or is an act of god. Now whether this is sincere or not, they still believe it.
3) Now I personally understand and accept that lightning is an electrical discharge, but I still believe that God (the Christian one) is capable of causing lighting - through the very nature of what I believe him to be like (all powerful). I can't prove this obviously other than from belief in what is he capable of...and I certainly believe in acts of God for the very simple fact that I hold a belief in God.
4) To support your argument you would have to show universal agreement that the new explanation (electrical discharge) has replaced the old explanation (act of god).
5) The trouble with that is that you would also have to show that God is in fact NOT or NO LONGER capable of producing lightning.
6) And to do that you would have to show that ALL gods that are worshipped either never existed, no longer exist, or if they do exist are incapable of producing lighting.[sic]
7) You would have to demonstrate this and convince all followers and believers of all the gods that are worshipped to stop worshipping them.
8) I don't think you can do this.
The whole point is that when you say the new explanation replaces the old explanation, you are making the assumption that there is universal agreement on the something replacing a need for god..
There isn't and won't be a universal agreement because we have the choice and freewill to accept and reject anything based on out own terms.
This is why I said this would only work for some people, and that for others the god explanation would be the correct explanation for them.
The key point here is that a need that is hardwired can be universal as we are all born with it as part of our DNA or genes.
But something like your description of lightning can't and won't ever be universal as it requires a change in belief and acceptance of something new to change a previous belief. There will always be someone who rejects something which is based on a belief.
And this is why I've previously made the distinction between a need for god and a belief in god....