I'm sort of inclined to side with the old-fashioned people who weren't speculating - I think deep, true love is possible in erotic and non-erotic friendships both, and the presence or absence of sex doesn't really matter. I tend to suspect that whether a romantic friendship is also erotic depends mostly on the participants - some people are more inclined toward sexual relationships, others more inclined toward "platonic". (In my experience, fanfic tastes go the same way - people who like smarm or who like slash are both into romantic friendships, but smarmers are people for whom sex is less important or meaningful than slashers...)