You Just HAVE to love mathematics! Oh to be able to involve Pythagoras in THIS debate.
Regarding the original question.... why the query? What difference does it make? Are we seeking an Ethnic, National or Cultural distinction as the subject of the delineation sought by the question?
Will Americans cease being "original founding father" American types due to the waves of European immigration in the late 1800s and mid 1900s, or the significant expansion of Spanish speaking Americans? Of course they're different. But are the founding principles forgotten? One hopes not.
Certainly any group identifies with who they are at any given time in history and directly relates with their group interests at that point in human affairs and development.
Hellenes historically have been Hellenes regardless of foreign or external infiltration incorporated over the passage of centuries. To their credit, Hellenes have managed through dogged determination to protect language, culture and, after Christ, their Christian faith, regardless of external occupation and approx. 452 years of slavery under the Ottoman Turks where Greek meant "slave". The Armenians have also felt this rule of less than "civilized" treatment as have the Jews prior to the founding of modern Israel. The latter have also always known who they are based upon faith and tradition.
Likewise, average contemporary Americans are vastly different in cultural and ethnic origin from one another and those who were contemporary during the nation's birth. Yet, they each identify themselves in some form or fashion with the mainstream in which they live, thus they are Americans by practice in daily social intercourse.
So, to be "as Greek" as the ancients is not a "traceable" or significant distinction. The question rather is, with how much of Ancient tradition and antiquity of the old, do the modern identify?
Of course, this is merely my humble untutored view of the matter.