If you are paying for everything yourselves without assistance, how did you determine the guest list? Are you inviting people who don’t have any relationship with you or fiancé to share your day to please everyone around you or are you limiting it to your closest friends and relatives? Who can you not imagine the day without? Those should be your priority guests. Everyone else can receive an announcement after the wedding.
While not everyone can afford or wants many random people in attendance they aren’t close to, parents can host guests in their home at another time or start a tradition of a family reunion picnic that you are not responsible for financing. It’s not like your wedding is the only event in their lives or the only party you will host as a couple.
Especially since the majority opinion is that a full dinner is the “minimum requirement” for proper hosting, which it is not, those do not come cheap and you can’t expect that every guest will “cover their plate” because an equal number do not give cash gifts nor is it their responsibility to pay for their dinner or drinks.