Sorry if this has been asked..
So I've been to MANY weddings where the cake is barely touched... I do not want a bakery supply of cake left over

What % of people do you think at a wedding actually eat the cake. Or any desert for that matter..My brother and sister in-law did a cookie bar.. I LOVED IT but they figured 2 cookies a person... they had more than half left...
Re: How much do people eat of cake?
If your crowd doesn't go overboard on cake, just have enough for one slice per person. Maybe see if your bakery can supply boxes for leftovers so your guests can take them with you.
FWIW, my wedding had cake, a cookie bar, a milkshake truck, and a chocolate fountain. The cookies I went overboard on, and we had about probably about 4 per person, if not more. Those we had the most leftovers for, and had boxes for cookies and cake people wanted to take. What was left after the majority of our guest left, we let the staff take. It was mostly cookies that remained.
If you take the time to find GOOD tasting cake - you won't have a crumb leftover - or in the case of the above just a few cupcakes. We had table cakes for 400 guests and of those, we pieced together 3 out of 50... In contradiction, a friend did table cakes at their wedding from a baker whose cake sucked and I think they had about 15 leftover.. At a cousin's wedding, her Mom made the cupcakes, and the ones she made there were none leftover, but the ones that the MIL made using grocery store rack tubs of frosting there were at least 50... If something tastes delish people WILL eat it whether that be cake, cookies, ice cream, etc.. I've been to at least four weddings and got told "Sorry, we ran out of cake" because they didn't order enough - and as a guest, that SUCKS!!!! I don't care if it's crummy frosting, I still prefer that over no opportunity for dessert of some sort!
So PLEASE- order enough cake/dessert for at least one slice per guest!!! (and put in the time to use someone whose product is delicious - yummy knows no price point - I've had top of the line bakers products that no one touched, and I've had bottom of the price point spectrum that there wasn't a crumb left..)
We had ~40 guests and ordered a cake to feed 75. My mom said there was about half left at the end of the night, but she brought it back to the hotel bar and alot of people had more there.