It's important, when scrutinising archaeological finds, that the observer maintains a very critical mind. It is very easy to project ideas, based on one's own preconceptions, onto an artifact or image. To use a mundane example, a piece of worked flint that looks perfectly shaped to be an animal-skin scraper should really be referred to as "a flake of knapped flint" until use-wear analysis can confirm the function of this tool type.

I'm guessing that your Ancient Egyptian "lightbulb" reference is pointing to the Dendera Crypts. Where you see a lightbulb, I see a flower with a possible snake coming out of it, all surrounded by an unidentified (to me) elongated bubble shape. The image should be viewed in context of the wider symbolic vocabulary of this period. The lack of supporting evidence for the existence of light bulbs at this time and place makes that interpretation less probable.

However, a good archaeologist will be open to any possibility. I think you'd find that many archaeologists, while upholding the most probable interpretations, will lend an ear to the least probable.

No, the evidence isn't ignored.