Points to always keep in mind (for everyone):
*Right or wrong, some persons grow dreaming on their marriage ceremony, as one of the top 3 moments of their lives.
*Family/friends might become a massive social pressure to get that high level event, and both need to address that early on.
*If pressure is indeed mounting, both should consider it like a prime test to see, if you will be able to handle difficult situations as a couple, later on.
*If either party (families included) won't compromise, nor reach a mutual decision without hard feelings, might be wise to reconsider marriage.
Also
*High spending does not equal better ceremony/celebration. Nor more memories (except bad ones).
*Ultimately, it's a day for you as a couple. Not just for one, and certainly not for others. Open celebration it's not an obligation.
*Depending country/culture, friends and family might be willing (on their own) to participate on preparing/getting food, organizing, hiring, pictures, etc.
That can cut a lot of spending, and it helps to develop a proper party environment, rather than a dry event.
But never push them to. That's not ok.
And, this always need to be stressed out, this is something that both need to be involved in.
Not just one, nor just one family. Both.