Ananda
The fact is that Greece's peripherality doesn't help. As has been pointed out LCCs don't like long sector lengths - however FR's wingleting of their 738s for example reduces fuel burn over longer sectors.
Up to recently most places nearby Greece were not open-skies however the EU expansion is changing that - there's also the small airspace problem to the southeast. If you looked at Ireland's air travel figures before open-skies you would think they didn't like travelling either - the increases since have been enormous.
I don't dispute your figures - I do think that they will increase and soon.