I can't imagine anyone can invite 100 active friends. Maybe I'm just too much of a loser to fathom that many, but I mean I do have a pretty broad definition of friend. Still only invited like 25 of my friends from all different times of my life. Add 25 for a spouse and 50 family, done: 100.

However, I could easily see inviting 100 family members in theory for myself, but it didn't pan out in practice. The generation before me, the weddings of my childhood, had a huge family turnout. They were grand/children of immigrants and still loved close by and gathered often. By time it was my turn though, they spread geographically and had all new close family members from their spouse's side. I invited 15.

So where do you go from there? Friends of friends. Coworkers. Inviting all your bosses/executives was a thing here. Acquaintances from minor prior interactions. Probably a bigger contributor is inviting all your parents' friends and coworkers because your parents want to show off. Sounds insane now, but it was just a thing they did. So "tertiary" might not even be disconnected enough. Plus the invite list can be much larger than the attendee list, with some courtesy invitations and possibly some strategic invitations to hope for gifts.

Some people just want to game it to be as big as they can make it. Some people have a list that big out of respect for family.

And if you do end up having a larger wedding and feel like some family member is a bit out of your life, if you don't dislike them, I recommend inviting them. The next time you see them will be at a funeral. Don't save it for that. But nothing wrong with keeping it small, either.