[E. Pluribus Unum]

I made a major theoretical breakthrough in the field of “energy creation”.

"Theoretical" being the operative word.

And why doesn't anybody use proper punctuation at the end of a sentence with quotes? Did they pass a law against it or something?

[rfreedom4u]

“Theoretical” being the operative word.

Yeah. I think the next time a bill collector calls me I’ll tell them I made a “theoretical” payment last week.

[sonofagun]

And why doesn't anybody use proper punctuation at the end of a sentence with quotes? Did they pass a law against it or something?

Because the proper punctuation feels so counter intuitive?

[Fhios]

I remember my fist time creating energy. It involved a plate of beans, a few beers and egg salad.

[Lonely Bull]

And why doesn't anybody use proper punctuation at the end of a sentence with quotes? Did they pass a law against it or something?

I don't know if the writer is using what many call a "British style," but it calls for placing that period outside the quotation mark. I've seen multiple examples from countries that tend to follow that style. (The rest of the quotation has other things that I'd edit: for example, I'd remove the comma from "The only way my theory leaves them, is to find a counter example to our theory.")