Yes, but the first sentence of that article reads, "Singular they has become the pronoun of choice to replace he and she in cases where the gender of the antecedent – the word the pronoun refers to – is unknown, irrelevant, or nonbinary, or where gender needs to be concealed."

According to your article, because the name of the actual person, Gustave Eiffel, is known the correct form of address is "Gustave Eiffel". Otherwise, no reader really knows who or how many people "they" references.