Large, lavish (for want of a better word) weddings and receptions can be a matter of personal desires and/or cultural expectations. As far as I am concerned, some are blatant fund-raisers. I would imagine that a civil wedding or a small, simple faith-based one, would simply not be considered acceptable in some communities.
It's not always a matter of affordability either; I know couples who have impoverished themselves for years into the future for want of the 'grand spectac'.
It's quite the range now; no wedding at all, simple ceremony, multi-thousand event-of-the-year. There was an article in The Star today how social media influencers (whatever the heck that is), are posting their weddings online with paid sponsorships for endorsements.