Bunbaker - I think back in the day weddings tended to have mainly family as guests and maybe one or two friends. These days it seems to be more friends than family. - this was because back in the day, the brides family (and sometimes the grooms) paid for the wedding. It was a party thrown by the parents of the couple, so the parents of the couple controlled the guest list and were hosting an event within their family/community.
Now, it's expected the couple will pay for the wedding, possibly with some financial help from parents, but I've only been to one wedding that was entirely funded by the parents of the couple, that was the wedding of a Hindu couple who had 500 guests, with one table of 20 of her friends, one table of 20 of his. The rest was extended family and family friends. Whole thing cost in the region of £40k. Now, if I was spending £40k on a party, I'd want it packed with people I care about, not people my parents think are important. If someone else is paying htat sort of money, I'd expect them to invite who they wanted.
Weddings have changed, the expectation is no longer that parents will fund weddings and that they are throwing a family event (just start a thread on here asking if it's "ok to get married with only 10 guests", everyone will say of course, it's more important that you focus on the marriage, not a big wedding). It's rarely a case that a marriage is seen as bringing together two families, it's seen as two people making a commitment to each other and throwing a party to celebrate that - it's much more about the couple and not the wider community. If it wasn't, you'd get more people up in arms at the suggestion of small weddings or just going off to get married without hosting a family/community event.
(And I'm not defending my own position, we had no children at our wedding, but that was because there were no children in the family and the only friends with DCs couldn't make it, but they were invited, mind you in hindsight, it was a very unDC friendly day, timings would have been a nightmare and the venue was really not safe for little ones)